Melamine formaldehyde: curing studies and reaction mechanism

<!DOCTYPE html> <html lang="en" class="grade-c"> <head> <title>Melamine formaldehyde: curing studies and reaction mechanism | Polymer Journal</title> <link rel="alternate" type="application/rss+xml" href="https://www.nature.com/pj.rss"/> <link rel="preconnect" href="https://cmp.nature.com" crossorigin> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="applicable-device" content="pc,mobile"> <meta name="viewport" content="width=device-width,initial-scale=1.0,maximum-scale=5,user-scalable=yes"> <meta name="360-site-verification" content="5a2dc4ab3fcb9b0393241ffbbb490480" /> <script data-test="dataLayer"> window.dataLayer = [{"content":{"category":{"contentType":"original article","legacy":{"webtrendsPrimaryArticleType":"research","webtrendsSubjectTerms":"mechanical-properties;polymer-characterization;polymer-synthesis;polymerization-mechanisms","webtrendsContentCategory":null,"webtrendsContentCollection":null,"webtrendsContentGroup":"Polymer 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The synthesized resins were characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA). Curing and reaction mechanism was studied by thermal and spectroscopic analysis. Two exothermic peaks were observed in the DSC analysis indicating a two-step crosslinking reaction process was correlated to TGA analysis. FTIR studies at different temperatures explained the two-stage curing mechanism which is concurring with the DSC data. At a temperature range of 140–160 °C, reversible demethylolation is dominating to the crosslinking reaction. At temperature >160 °C, the crosslinking reaction dominates. On the basis of DSC and FTIR data, a possible crosslinking reaction route was derived and explained. The first stage of curing is the conversion of methylol groups to primary amine and the second stage is the crosslinking of methylol groups to the final product, methylene bridges. The thermal stability of the methylol groups, methylene bridges and the triazine ring, as well as the evaporation of effluents at different stages of curing, are also discussed based on combined TGA and DSC results. Curing studies and reaction mechanism of MF resin was studied by thermal and spectroscopic tools comparing DSC and FTIR studies explains the two-stage thermal curing mechanism. The first step of thermal curing at temperature range of 140–160 °C is the reverse reaction of methylol groups to melamine and second step occurring at temperature >160 °C is the crosslinking of methylol groups to the final product, methylene bridge. Hence, by the mutual agreement of DSC and FTIR studies, a possible reaction route was derived for the thermal curing process. The DSC–TGA thermogram supports the two-step process of the cure reaction by exhibiting two peaks in the same temperature region.\n \n \n \n ","datePublished":"2012-10-17T00:00:00Z","dateModified":"2012-10-17T00:00:00Z","pageStart":"413","pageEnd":"419","sameAs":"https://doi.org/10.1038/pj.2012.162","keywords":["Mechanical properties","Polymer characterization","Polymer synthesis","Polymerization mechanisms","curing","melamine formaldehyde","thermal properties","thermosetting resin","Chemistry/Food Science","general","Polymer Sciences","Biomaterials","Surfaces and Interfaces","Thin Films","Bioorganic Chemistry"],"image":["https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figa_HTML.jpg","https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fig1_HTML.jpg","https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fig2_HTML.jpg","https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fig3_HTML.jpg","https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figd_HTML.jpg","https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fig4_HTML.jpg","https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fige_HTML.gif","https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figf_HTML.gif","https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figg_HTML.gif","https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figh_HTML.gif","https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figb_HTML.jpg","https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figc_HTML.jpg"],"isPartOf":{"name":"Polymer Journal","issn":["1349-0540","0032-3896"],"volumeNumber":"45","@type":["Periodical","PublicationVolume"]},"publisher":{"name":"Nature Publishing Group UK","logo":{"url":"https://www.springernature.com/app-sn/public/images/logo-springernature.png","@type":"ImageObject"},"@type":"Organization"},"author":[{"name":"Dyana J Merline","affiliation":[{"name":"The Petroleum Institute","address":{"name":"Department of Chemical Engineering, The Petroleum Institute, Abu Dhabi, UAE","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Sulafudin Vukusic","affiliation":[{"name":"The Petroleum Institute","address":{"name":"Department of Chemical Engineering, The Petroleum Institute, Abu Dhabi, UAE","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Ahmed A Abdala","affiliation":[{"name":"The Petroleum Institute","address":{"name":"Department of Chemical Engineering, The Petroleum Institute, Abu Dhabi, UAE","@type":"PostalAddress"},"@type":"Organization"}],"email":"aabdala@pi.ac.ae","@type":"Person"}],"isAccessibleForFree":true,"@type":"ScholarlyArticle"},"@context":"https://schema.org","@type":"WebPage"}</script> <link rel="canonical" href="https://www.nature.com/articles/pj2012162"> <meta name="journal_id" content="41428"/> <meta name="dc.title" content="Melamine formaldehyde: curing studies and reaction mechanism"/> <meta name="dc.source" content="Polymer Journal 2013 45:4"/> <meta name="dc.format" content="text/html"/> <meta name="dc.publisher" content="Nature Publishing Group"/> <meta name="dc.date" content="2012-10-17"/> <meta name="dc.type" content="OriginalPaper"/> <meta name="dc.language" content="En"/> <meta name="dc.copyright" content="2013 The Society of Polymer Science, Japan"/> <meta name="dc.rights" content="2013 The Society of Polymer Science, Japan"/> <meta name="dc.rightsAgent" content="journalpermissions@springernature.com"/> <meta name="dc.description" content="Melamine formaldehyde (MF) resin was synthesized by the reaction between melamine and formaldehyde under alkaline condition in tetrohydrofuran medium with 1:3 melamine to formaldehyde molar ratio. The synthesized resins were characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA). Curing and reaction mechanism was studied by thermal and spectroscopic analysis. Two exothermic peaks were observed in the DSC analysis indicating a two-step crosslinking reaction process was correlated to TGA analysis. FTIR studies at different temperatures explained the two-stage curing mechanism which is concurring with the DSC data. At a temperature range of 140–160 °C, reversible demethylolation is dominating to the crosslinking reaction. At temperature &gt;160 °C, the crosslinking reaction dominates. On the basis of DSC and FTIR data, a possible crosslinking reaction route was derived and explained. The first stage of curing is the conversion of methylol groups to primary amine and the second stage is the crosslinking of methylol groups to the final product, methylene bridges. The thermal stability of the methylol groups, methylene bridges and the triazine ring, as well as the evaporation of effluents at different stages of curing, are also discussed based on combined TGA and DSC results. Curing studies and reaction mechanism of MF resin was studied by thermal and spectroscopic tools comparing DSC and FTIR studies explains the two-stage thermal curing mechanism. The first step of thermal curing at temperature range of 140–160 °C is the reverse reaction of methylol groups to melamine and second step occurring at temperature &gt;160 °C is the crosslinking of methylol groups to the final product, methylene bridge. Hence, by the mutual agreement of DSC and FTIR studies, a possible reaction route was derived for the thermal curing process. 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The thermal stability of the methylol groups, methylene bridges and the triazine ring, as well as the evaporation of effluents at different stages of curing, are also discussed based on combined TGA and DSC results. Curing studies and reaction mechanism of MF resin was studied by thermal and spectroscopic tools comparing DSC and FTIR studies explains the two-stage thermal curing mechanism. The first step of thermal curing at temperature range of 140–160 °C is the reverse reaction of methylol groups to melamine and second step occurring at temperature &gt;160 °C is the crosslinking of methylol groups to the final product, methylene bridge. Hence, by the mutual agreement of DSC and FTIR studies, a possible reaction route was derived for the thermal curing process. 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Biodegradat.; citation_title=Biodegradation of melamine formaldehyde by micrococcus sp. strain MF-1 isolated from aminoplastic waste water effluent; citation_author=WS El-Sayed, AF El-Baz, AM Othman; citation_volume=57; citation_publication_date=2006; citation_pages=75-81; citation_doi=10.1016/j.ibiod.2005.11.006; citation_id=CR5"/> <meta name="citation_reference" content="citation_journal_title=Ind. Eng. Chem.; citation_title=Polymerisation in melamine-formaldehyde molded resins; citation_author=HP Wohnsiedler; citation_volume=45; citation_publication_date=1953; citation_pages=2307-2311; citation_doi=10.1021/ie50526a045; citation_id=CR6"/> <meta name="citation_reference" content="citation_journal_title=J. Appl. Polym. Sci.; citation_title=Using isoconventional kinetic analysis of liquid melamine-formaldehyde resin curing to predict laminate surface properties; citation_author=A Kandelbauer, G Wuzella, A Mahendran, I Taudes, P Widsten; citation_volume=113; citation_publication_date=2009; citation_pages=2649-2660; citation_doi=10.1002/app.30294; citation_id=CR7"/> <meta name="citation_reference" content="citation_journal_title=Chem. Eng. J.; citation_title=Model-free kinetic analysis of melamine-formaldehyde resin cure; citation_author=A Kandelbauer, G Wuzella, A Mahendran, I Taudes, P Widsten; citation_volume=152; citation_publication_date=2009; citation_pages=556-565; citation_doi=10.1016/j.cej.2009.05.027; citation_id=CR8"/> <meta name="citation_reference" content="citation_journal_title=J. Am. Chem. Soc.; citation_title=Kinetics of condensation of melamine with formaldehyde; citation_author=BM Okano, Y Ogata; citation_volume=74; citation_publication_date=1952; citation_pages=5728-5732; citation_doi=10.1021/ja01142a047; citation_id=CR9"/> <meta name="citation_reference" content="citation_journal_title=Macromol. Symp.; citation_title=Studies on the stability of MF resin solutions: investigations on network formation; citation_author=J Mijatowic, WH Binder, F Kubel, W Kantner; citation_volume=181; citation_publication_date=2002; citation_pages=373-382; citation_doi=10.1002/1521-3900(200205)181:1<373::AID-MASY373>3.0.CO;2-J; citation_id=CR10"/> <meta name="citation_reference" content="citation_journal_title=J. Poly. Sci. Poly. Chem. Edi.; citation_title=Melamine–formaldehyde resins: molecular species distributions of methylolmelamines and some kinetics of methylolation; citation_author=B Tomita; citation_volume=15; citation_publication_date=1977; citation_pages=2347-2365; citation_doi=10.1002/pol.1977.170151005; citation_id=CR11"/> <meta name="citation_reference" content="citation_journal_title=J. Poly. Sci. Poly. Chem. Edi.; citation_title=Melamine–Formaldehyde resins: constitutional characterization by C-13 fourier transform NMR spectroscopy; citation_author=B Tomita, H Ono; citation_volume=17; citation_publication_date=1979; citation_pages=3205-3215; citation_doi=10.1002/pol.1979.170171012; citation_id=CR12"/> <meta name="citation_reference" content="citation_journal_title=Spectrosc. Br. Poly. J.; citation_title=Characterisation of some melamine-formaldehyde condensates and some cured resins by 1H, 13C and 15N n.m.r; citation_author=JR Ebdon, BJ Hunt, WTS O’Rourke, J Parkin; citation_volume=20; citation_publication_date=1988; citation_pages=327-334; citation_doi=10.1002/pi.4980200405; citation_id=CR13"/> <meta name="citation_reference" content="citation_journal_title=Polymer; citation_title=Examination of some melamine formaldehyde adduct by C13 nuclear magnetic resonance; citation_author=M Dawbarn, JR Ebdon, SJ Hewitt; citation_volume=19; citation_publication_date=1978; citation_pages=1309-1312; citation_doi=10.1016/0032-3861(78)90312-9; citation_id=CR14"/> <meta name="citation_reference" content="citation_journal_title=J. Appl. Poly. Sci.; citation_title=Preparation and characterisation of melamine-formaldehyde-polyvinylpyrrolidone polymer resin for better industrial uses over melamine resin; citation_author=M Sing, M Kumar; citation_volume=114; citation_publication_date=2009; citation_pages=1870-1878; citation_doi=10.1002/app.30805; citation_id=CR15"/> <meta name="citation_reference" content="citation_title=The Chemistry of Polymerization Processes, SCI Monograph No. 20; citation_publication_date=1965; citation_id=CR16; citation_author=M Gordon; citation_author=A Halliwell; citation_author=T Wilson; citation_publisher=Society of Chemical Industry, London"/> <meta name="citation_reference" content="citation_journal_title=Poly. J.; citation_title=Studies on melamine resin: kinetics of acid-catalysed condensation of di and trimethylolmelamine; citation_author=K Sato, T Naito; citation_volume=5; citation_publication_date=1973; citation_pages=144-157; citation_doi=10.1295/polymj.5.144; citation_id=CR17"/> <meta name="citation_reference" content="citation_journal_title=Ange. Makro. Chemie.; citation_title=Investigation of the melamine formadehyde reaction products; citation_author=D Braun, V Legradic; citation_volume=36; citation_publication_date=1974; citation_pages=41-55; citation_doi=10.1002/apmc.1974.050360104; citation_id=CR18"/> <meta name="citation_reference" content="citation_journal_title=Thermo. Acta; citation_title=Thermogravimetry/fourier transform infrared coupling investigations to study the thermal stability of melamine formaldehyde resin; citation_author=C Devallencourt, JM Saiter, A Fafet, E Ubrich; citation_volume=259; citation_publication_date=1995; citation_pages=143-151; citation_doi=10.1016/0040-6031(95)02262-Z; citation_id=CR19"/> <meta name="citation_reference" content="citation_journal_title=J. Poly. Sci. Symp.; citation_title=Thermal stability of melamine formaldehyde resins; citation_author=TR Manley, DA Higgs; citation_volume=42; citation_publication_date=1973; citation_pages=1377-1382; citation_doi=10.1002/polc.5070420337; citation_id=CR20"/> <meta name="citation_reference" content="citation_journal_title=J. Appl. Chem.; citation_title=Thermal degradation of melamine formaldehyde resins; citation_author=WR Moore, E Donnelly; citation_volume=13; citation_publication_date=1963; citation_pages=537-543; citation_doi=10.1002/jctb.5010131202; citation_id=CR21"/> <meta name="citation_reference" content="citation_journal_title=Polymer; citation_title=Synthesis of the melamine–formaldehyde polycondensate and its thermal stabilization effect on polyoxymethylene; citation_author=H Youliang, Y Lin, Z Xiaowen; citation_volume=47; citation_publication_date=2006; citation_pages=2649-2659; citation_doi=10.1016/j.polymer.2006.02.050; citation_id=CR22"/> <meta name="citation_reference" content="citation_journal_title=J. Chromat. A; citation_title=Improved analysis of melamine-formaldehyde resins by capillary zone electrophoresis-mass spectrometry using ion-trap and quadrupole-time-of-flight mass spectrometers; citation_author=DT Vo, M Himmelsbach, M Haunschmidt, W Buchberger, C Schwarzinger, CW Klambfl; citation_volume=1213; citation_publication_date=2008; citation_pages=83-87; citation_doi=10.1016/j.chroma.2008.07.002; citation_id=CR23"/> <meta name="citation_reference" content="citation_journal_title=Polymer; citation_title=Melamine formaldehyde compounds. The active species in acid catalyzed reactions; citation_author=A Berge, T Mejdell; citation_volume=47; citation_publication_date=2006; citation_pages=3249-3256; citation_doi=10.1016/j.polymer.2006.02.054; citation_id=CR24"/> <meta name="citation_reference" content="citation_journal_title=J. Macromol. Sci. Chem. A; citation_title=The initial stage of the reaction of melamine with formaldehyde; citation_author=R Naske, K Dietrich, G Reinisch, G Refler; citation_volume=23; citation_publication_date=1986; citation_pages=579-596; citation_doi=10.1080/00222338608058497; citation_id=CR25"/> <meta name="citation_reference" content="citation_journal_title=J. Poly. Sci. Poly. Phys. Ed.; citation_title=Crosslinking chemistry and network structure in organic coatings. I. Cure of melamine formaldehyde/acrylic copolymer films; citation_author=DR Bauer, RA Dickie; citation_volume=18; citation_publication_date=1980; citation_pages=1997-2014; citation_doi=10.1002/pol.1980.180181001; citation_id=CR26"/> <meta name="citation_reference" content="citation_journal_title=Prog. Org. Coat.; citation_title=Melamine/formaldehyde crosslinkers: characterization, network formation and crosslink degradation; citation_author=BR David; citation_volume=14; citation_publication_date=1986; citation_pages=193-218; citation_doi=10.1016/0033-0655(86)80001-2; citation_id=CR27"/> <meta name="citation_reference" content="citation_journal_title=Vibrat. Spect.; citation_title=Study of cross-linking reactions of melamine/formaldehyde resin with hydroxyl functional polyester by generalized 2-D infrared spectroscopy; citation_author=RC Wilson, WF Pfohl; citation_volume=23; citation_publication_date=2000; citation_pages=13-22; citation_doi=10.1016/S0924-2031(99)00072-7; citation_id=CR28"/> <meta name="citation_reference" content="citation_journal_title=Vibrat. Spect.; citation_title=Investigation of melamine-formaldehyde cure by fourier transform Raman spectroscopy; citation_author=ML Scheepers, JM Gelan, RA Carleer, PJ Adriaensens, DJ Vanderzande; citation_volume=6; citation_publication_date=1993; citation_pages=55-69; citation_doi=10.1016/0924-2031(93)87022-L; citation_id=CR29"/> <meta name="citation_reference" content="citation_journal_title=Polymer; citation_title=Nano-structure phosphorus-containing polyurethane dispersions: synthesis and crosslinking with melamine formaldehyde resin; citation_author=K Mequanint, R Sanderson; citation_volume=44; citation_publication_date=2003; citation_pages=2631-2639; citation_doi=10.1016/S0032-3861(03)00154-X; citation_id=CR30"/> <meta name="citation_reference" content="citation_journal_title=Macromol. Symp.; citation_title=The reaction mechanism of the transetherification and crosslinking of melamine resins; citation_author=R Manfred, B Hartmut, I Sergey, P Valery, L Paul, ON Primachenko; citation_volume=217; citation_publication_date=2004; citation_pages=431-443; citation_doi=10.1002/masy.200451339; citation_id=CR31"/> <meta name="citation_reference" content="citation_journal_title=J. Coat. Techn.; citation_title=Reaction mechanism of amino resin; citation_author=WJ Blank; citation_volume=51; citation_publication_date=1979; citation_pages=61-70; citation_id=CR32"/> <meta name="citation_reference" content="citation_journal_title=Br. Polym. J.; citation_title=Melamine-formaldehyde resins: an examination of some model compound systems; citation_author=IH Anderson, M Cawley, W Steedman; citation_volume=1; citation_publication_date=1969; citation_pages=24-28; citation_doi=10.1002/pi.4980010104; citation_id=CR33"/> <meta name="citation_reference" content="citation_journal_title=Polymer; citation_title=Examination of some melamine formaldehyde adduct by C13 nuclear magnetic resonance; citation_author=M Dawbarn, JR Ebdon, SJ Hewitt; citation_volume=19; citation_publication_date=1978; citation_pages=1309-1312; citation_doi=10.1016/0032-3861(78)90312-9; citation_id=CR34"/> <meta name="citation_reference" content="citation_title=Handbook of Adhesive Technology; citation_publication_date=2003; citation_id=CR35; citation_author=A Pizzi; citation_publisher=Marcel Dekker, France, Inc."/> <meta name="citation_author" content="Merline, Dyana J"/> <meta name="citation_author_institution" content="Department of Chemical Engineering, The Petroleum Institute, Abu Dhabi, UAE"/> <meta name="citation_author" content="Vukusic, Sulafudin"/> <meta name="citation_author_institution" content="Department of Chemical Engineering, The Petroleum Institute, Abu Dhabi, UAE"/> <meta name="citation_author" content="Abdala, Ahmed A"/> <meta name="citation_author_institution" content="Department of Chemical Engineering, The Petroleum Institute, Abu Dhabi, UAE"/> <meta name="access_endpoint" content="https://www.nature.com/platform/readcube-access"/> <meta name="twitter:site" content="@Polymer_Journal"/> <meta name="twitter:card" content="summary_large_image"/> <meta name="twitter:image:alt" content="Content cover image"/> <meta name="twitter:title" content="Melamine formaldehyde: curing studies and reaction mechanism"/> <meta name="twitter:description" content="Polymer Journal - Curing studies and reaction mechanism of MF resin was studied by thermal and spectroscopic tools comparing DSC and FTIR studies explains the two-stage thermal curing mechanism...."/> <meta name="twitter:image" content="https://media.springernature.com/full/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fig1_HTML.jpg"/> <meta property="og:url" content="https://www.nature.com/articles/pj2012162"/> <meta property="og:type" content="article"/> <meta property="og:site_name" content="Nature"/> <meta property="og:title" content="Melamine formaldehyde: curing studies and reaction mechanism - Polymer Journal"/> <meta property="og:description" content="Curing studies and reaction mechanism of MF resin was studied by thermal and spectroscopic tools comparing DSC and FTIR studies explains the two-stage thermal curing mechanism. The first step of thermal curing at temperature range of 140–160 °C is the reverse reaction of methylol groups to melamine and second step occurring at temperature &gt;160 °C is the crosslinking of methylol groups to the final product, methylene bridge. Hence, by the mutual agreement of DSC and FTIR studies, a possible reaction route was derived for the thermal curing process. 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data-article-pdf="true" data-readcube-pdf-url="true" data-test="download-pdf" data-draft-ignore="true" data-track="content_download" data-track-type="article pdf download" data-track-action="download pdf" data-track-label="link" data-track-external download> <span class="c-pdf-download__text">Download PDF</span> <svg aria-hidden="true" focusable="false" width="16" height="16" class="u-icon"><use xlink:href="#icon-download"/></svg> </a> </div> </div> </div> <article lang="en"> <div class="c-pdf-button__container u-mb-16 u-hide-at-lg js-context-bar-sticky-point-mobile"> <div class="c-pdf-container" data-track-context="article body"> <div class="c-pdf-download u-clear-both js-pdf-download"> <a href="/articles/pj2012162.pdf" class="u-button u-button--full-width u-button--primary u-justify-content-space-between c-pdf-download__link" data-article-pdf="true" data-readcube-pdf-url="true" data-test="download-pdf" data-draft-ignore="true" data-track="content_download" data-track-type="article pdf download" data-track-action="download pdf" data-track-label="link" data-track-external download> <span class="c-pdf-download__text">Download PDF</span> <svg aria-hidden="true" focusable="false" width="16" height="16" class="u-icon"><use xlink:href="#icon-download"/></svg> </a> </div> </div> </div> <div class="c-article-header"> <header> <ul class="c-article-identifiers" data-test="article-identifier"> <li class="c-article-identifiers__item" data-test="article-category">Original Article</li> <li class="c-article-identifiers__item">Published: <time datetime="2012-10-17">17 October 2012</time></li> </ul> <p class="c-article-title__super">Polymer Synthesis and Reactions</p><h1 class="c-article-title" data-test="article-title" data-article-title="">Melamine formaldehyde: curing studies and reaction mechanism</h1> <ul class="c-article-author-list c-article-author-list--short" data-test="authors-list" data-component-authors-activator="authors-list"><li class="c-article-author-list__item"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Dyana_J-Merline-Aff1" data-author-popup="auth-Dyana_J-Merline-Aff1" data-author-search="Merline, Dyana J">Dyana J Merline</a><sup class="u-js-hide"><a href="#Aff1">1</a></sup>, </li><li class="c-article-author-list__item"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Sulafudin-Vukusic-Aff1" data-author-popup="auth-Sulafudin-Vukusic-Aff1" data-author-search="Vukusic, Sulafudin">Sulafudin Vukusic</a><sup class="u-js-hide"><a href="#Aff1">1</a></sup> & </li><li class="c-article-author-list__item"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Ahmed_A-Abdala-Aff1" data-author-popup="auth-Ahmed_A-Abdala-Aff1" data-author-search="Abdala, Ahmed A" data-corresp-id="c1">Ahmed A Abdala<svg width="16" height="16" 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c-article-metrics-bar__item" data-test="access-count"> <p class="c-article-metrics-bar__count">65k <span class="c-article-metrics-bar__label">Accesses</span></p> </li> <li class="c-article-metrics-bar__item" data-test="citation-count"> <p class="c-article-metrics-bar__count">332 <span class="c-article-metrics-bar__label">Citations</span></p> </li> <li class="c-article-metrics-bar__item" data-test="altmetric-score"> <p class="c-article-metrics-bar__count">12 <span class="c-article-metrics-bar__label">Altmetric</span></p> </li> <li class="c-article-metrics-bar__item"> <p class="c-article-metrics-bar__details"><a href="/articles/pj2012162/metrics" data-track="click" data-track-action="view metrics" data-track-label="link" rel="nofollow">Metrics <span class="u-visually-hidden">details</span></a></p> </li> </ul> </div> </header> <div class="u-js-hide" data-component="article-subject-links"> <h3 class="c-article__sub-heading">Subjects</h3> <ul class="c-article-subject-list"> <li class="c-article-subject-list__subject"><a href="/subjects/mechanical-properties" data-track="click" data-track-action="view subject" data-track-label="link">Mechanical properties</a></li><li class="c-article-subject-list__subject"><a href="/subjects/polymer-characterization" data-track="click" data-track-action="view subject" data-track-label="link">Polymer characterization</a></li><li class="c-article-subject-list__subject"><a href="/subjects/polymer-synthesis" data-track="click" data-track-action="view subject" data-track-label="link">Polymer synthesis</a></li><li class="c-article-subject-list__subject"><a href="/subjects/polymerization-mechanisms" data-track="click" data-track-action="view subject" data-track-label="link">Polymerization mechanisms</a></li> </ul> </div> </div> <div class="c-article-body"> <section aria-labelledby="Abs1" data-title="Abstract" lang="en"><div class="c-article-section" id="Abs1-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="Abs1">Abstract</h2><div class="c-article-section__content" id="Abs1-content"><p>Melamine formaldehyde (MF) resin was synthesized by the reaction between melamine and formaldehyde under alkaline condition in tetrohydrofuran medium with 1:3 melamine to formaldehyde molar ratio. The synthesized resins were characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA). Curing and reaction mechanism was studied by thermal and spectroscopic analysis. Two exothermic peaks were observed in the DSC analysis indicating a two-step crosslinking reaction process was correlated to TGA analysis. FTIR studies at different temperatures explained the two-stage curing mechanism which is concurring with the DSC data. At a temperature range of 140–160 °C, reversible demethylolation is dominating to the crosslinking reaction. At temperature >160 °C, the crosslinking reaction dominates. On the basis of DSC and FTIR data, a possible crosslinking reaction route was derived and explained. The first stage of curing is the conversion of methylol groups to primary amine and the second stage is the crosslinking of methylol groups to the final product, methylene bridges. The thermal stability of the methylol groups, methylene bridges and the triazine ring, as well as the evaporation of effluents at different stages of curing, are also discussed based on combined TGA and DSC results.</p></div></div></section> <section aria-labelledby="inline-recommendations" data-title="Inline Recommendations" class="c-article-recommendations" data-track-component="inline-recommendations"> <h3 class="c-article-recommendations-title" id="inline-recommendations">Similar content being viewed by others</h3> <div class="c-article-recommendations-list"> <div class="c-article-recommendations-list__item"> <article class="c-article-recommendations-card" itemscope itemtype="http://schema.org/ScholarlyArticle"> <div class="c-article-recommendations-card__img"><img src="https://media.springernature.com/w215h120/springer-static/image/art%3A10.1038%2Fs41428-020-0380-3/MediaObjects/41428_2020_380_Figa_HTML.png" loading="lazy" alt=""></div> <div class="c-article-recommendations-card__main"> <h3 class="c-article-recommendations-card__heading" itemprop="name headline"> <a class="c-article-recommendations-card__link" itemprop="url" href="https://www.nature.com/articles/s41428-020-0380-3?fromPaywallRec=false" data-track="select_recommendations_1" data-track-context="inline recommendations" data-track-action="click recommendations inline - 1" data-track-label="10.1038/s41428-020-0380-3">Curing acceleration of cyanate ester resin by a phenolic compound having a tertiary amino group at the ortho-position </a> </h3> <div class="c-article-meta-recommendations" data-test="recommendation-info"> <span class="c-article-meta-recommendations__item-type">Article</span> <span class="c-article-meta-recommendations__date">23 June 2020</span> </div> </div> </article> </div> <div class="c-article-recommendations-list__item"> <article class="c-article-recommendations-card" itemscope itemtype="http://schema.org/ScholarlyArticle"> <div class="c-article-recommendations-card__img"><img src="https://media.springernature.com/w215h120/springer-static/image/art%3A10.1038%2Fs41598-022-17316-7/MediaObjects/41598_2022_17316_Fig1_HTML.png" loading="lazy" alt=""></div> <div class="c-article-recommendations-card__main"> <h3 class="c-article-recommendations-card__heading" itemprop="name headline"> <a class="c-article-recommendations-card__link" itemprop="url" href="https://www.nature.com/articles/s41598-022-17316-7?fromPaywallRec=false" data-track="select_recommendations_2" data-track-context="inline recommendations" data-track-action="click recommendations inline - 2" data-track-label="10.1038/s41598-022-17316-7">A novel treatment and derivatization for quantification of residual aromatic diisocyanates in polyamide resins </a> </h3> <div class="c-article-meta-recommendations" data-test="recommendation-info"> <span class="c-article-meta-recommendations__item-type">Article</span> <span class="c-article-meta-recommendations__access-type">Open access</span> <span class="c-article-meta-recommendations__date">29 July 2022</span> </div> </div> </article> </div> <div class="c-article-recommendations-list__item"> <article class="c-article-recommendations-card" itemscope itemtype="http://schema.org/ScholarlyArticle"> <div class="c-article-recommendations-card__img"><img src="https://media.springernature.com/w215h120/springer-static/image/art%3A10.1038%2Fs41428-021-00583-y/MediaObjects/41428_2021_583_Figa_HTML.png" loading="lazy" alt=""></div> <div class="c-article-recommendations-card__main"> <h3 class="c-article-recommendations-card__heading" itemprop="name headline"> <a class="c-article-recommendations-card__link" itemprop="url" href="https://www.nature.com/articles/s41428-021-00583-y?fromPaywallRec=false" data-track="select_recommendations_3" data-track-context="inline recommendations" data-track-action="click recommendations inline - 3" data-track-label="10.1038/s41428-021-00583-y">Tuning the thermal and mechanical properties of poly(vinyl alcohol) with 2,5-furandicarboxylic acid acting as a biobased crosslinking agent </a> </h3> <div class="c-article-meta-recommendations" data-test="recommendation-info"> <span class="c-article-meta-recommendations__item-type">Article</span> <span class="c-article-meta-recommendations__date">18 November 2021</span> </div> </div> </article> </div> </div> </section> <script> window.dataLayer = window.dataLayer || []; window.dataLayer.push({ recommendations: { recommender: 'semantic', model: 'specter', policy_id: 'NA', timestamp: 1744308799, embedded_user: 'null' } }); </script> <div class="main-content"> <section data-title="Introduction"><div class="c-article-section" id="Sec1-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="Sec1">Introduction</h2><div class="c-article-section__content" id="Sec1-content"><p>Melamine (1, 3, 5-triamino-2, 4, 6-triazine) formaldehyde (MF) is one of the hardest and stiffest thermosetting polymers, which provides good properties and performance. It is an amino resin and has various material advantages, such as transparency, better hardness, thermal stability, excellent boil resistance, scratch resistance, abrasion resistance, flame retardant, moisture resistance and surface smoothness, which lead MF to large industrial applications.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 1" title="Bajia, S., Sharma, R. & Bajia, B. Solid-state microwave synthesis of melamine formaldehyde resin. J. Chem. 6, 120–124 (2009)." href="/articles/pj2012162#ref-CR1" id="ref-link-section-d5920135e345">1</a></sup> These polymers were originally used as wood adhesives and have now found applications in flooring and decorative laminates, molding compounds, coatings and adhesives.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 2" title="Park, B. -D. & Jeong, H. -W. Cure kinetics of melamine-formaldehyde resin/clay/cellulose nanocomposites. J. Ind. Eng. Chem. 16, 375–379 (2010)." href="/articles/pj2012162#ref-CR2" id="ref-link-section-d5920135e349">2</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 3" title="Dipak, K. R., Amit, J. P. & Bhavi, N. N. A Study on composites from casein modified melamine formaldehyde resin. Poly. Plast. Tech. Eng. 45, 293–299 (2006)." href="/articles/pj2012162#ref-CR3" id="ref-link-section-d5920135e352">3</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 4" title="Anil, K. & Vimal, K. Modelling and experimental investigation of melamine formaldehyde polymerization. Macromolecules 23, 3729–3736 (1990)." href="/articles/pj2012162#ref-CR4" id="ref-link-section-d5920135e355">4</a></sup> MF resins are incorporated in wide variety of products that are valued for its toughness and relative ease of manufacture.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 5" title="El-Sayed, W. S., El-Baz, A. F. & Othman, A. M. Biodegradation of melamine formaldehyde by micrococcus sp. strain MF-1 isolated from aminoplastic waste water effluent. Int. Biodeteriorat. Biodegradat. 57, 75–81 (2006)." href="/articles/pj2012162#ref-CR5" id="ref-link-section-d5920135e359">5</a></sup> The curing behavior and the degree of crosslinking of MF resin determine the tailored product properties such as mechanical, thermal and electrical properties.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 6" title="Wohnsiedler, H. P. Polymerisation in melamine-formaldehyde molded resins. Ind. Eng. Chem. 45, 2307–2311 (1953)." href="/articles/pj2012162#ref-CR6" id="ref-link-section-d5920135e363">6</a></sup> Cured MF polymers are sufficiently hard and exhibit high resistance against temperature, chemicals and hydrolysis, making them suitable for interior working surfaces.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 7" title="Kandelbauer, A., Wuzella, G., Mahendran, A., Taudes, I. & Widsten, P. Using isoconventional kinetic analysis of liquid melamine-formaldehyde resin curing to predict laminate surface properties. J. Appl. Polym. Sci. 113, 2649–2660 (2009)." href="/articles/pj2012162#ref-CR7" id="ref-link-section-d5920135e367">7</a></sup> If the resin is not cured properly, MF will lack mechanical strength and surface finishes. For example, MF impregnated papers will lack hardness, durability, brilliance and resistance to hydrolysis and chemical agents.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 8" title="Kandelbauer, A., Wuzella, G., Mahendran, A., Taudes, I. & Widsten, P. Model-free kinetic analysis of melamine-formaldehyde resin cure. Chem. Eng. J. 152, 556–565 (2009)." href="/articles/pj2012162#ref-CR8" id="ref-link-section-d5920135e372">8</a></sup> The condensation reaction and the resulting structure of MF resins vary significantly with the reaction conditions such as molar ratios of the reactants, pH and reaction temperature profiles during resin preparation.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 9" title="Okano, B. M. & Ogata, Y. Kinetics of condensation of melamine with formaldehyde. J. Am. Chem. Soc. 74, 5728–5732 (1952)." href="/articles/pj2012162#ref-CR9" id="ref-link-section-d5920135e376">9</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 10" title="Mijatowic, J., Binder, W. H., Kubel, F. & Kantner, W. Studies on the stability of MF resin solutions: investigations on network formation. Macromol. Symp. 181, 373–382 (2002)." href="/articles/pj2012162#ref-CR10" id="ref-link-section-d5920135e379">10</a></sup> Thus, curing studies of MF resins finds immense importance.</p><p>Several research groups have studied the reaction of melamine with formaldehyde. Studies on the addition reaction between melamine and formaldehyde by means of reversed-phase liquid chromatography has been reported.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 11" title="Tomita, B. Melamine–formaldehyde resins: molecular species distributions of methylolmelamines and some kinetics of methylolation. J. Poly. Sci. Poly. Chem. Edi. 15, 2347–2365 (1977)." href="/articles/pj2012162#ref-CR11" id="ref-link-section-d5920135e386">11</a></sup> All of the nine methylol melamines could be assigned and the technique can also be applied to the quantitative analysis of methylol melamines in the reaction mixtures. Several authors<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 12" title="Tomita, B. & Ono, H. Melamine–Formaldehyde resins: constitutional characterization by C-13 fourier transform NMR spectroscopy. J. Poly. Sci. Poly. Chem. Edi. 17, 3205–3215 (1979)." href="/articles/pj2012162#ref-CR12" id="ref-link-section-d5920135e390">12</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 13" title="Ebdon, J. R., Hunt, B. J., O’Rourke, W. T. S. & Parkin, J. Characterisation of some melamine-formaldehyde condensates and some cured resins by 1H, 13C and 15N n.m.r. Spectrosc. Br. Poly. J. 20, 327–334 (1988)." href="/articles/pj2012162#ref-CR13" id="ref-link-section-d5920135e393">13</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 14" title="Dawbarn, M., Ebdon, J. R. & Hewitt, S. J. Examination of some melamine formaldehyde adduct by C13 nuclear magnetic resonance. Polymer 19, 1309–1312 (1978)." href="/articles/pj2012162#ref-CR14" id="ref-link-section-d5920135e396">14</a></sup> have studied the reactions and structures of soluble MF resins by means of <sup>13</sup>C nuclear magnetic resonance (NMR). The structure elucidation of melamine–formaldehyde–polyvinylpyrrolidone by <sup>1</sup>H NMR and <sup>13</sup>C NMR has been reported.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 15" title="Sing, M. & Kumar, M. Preparation and characterisation of melamine-formaldehyde-polyvinylpyrrolidone polymer resin for better industrial uses over melamine resin. J. Appl. Poly. Sci. 114, 1870–1878 (2009)." href="/articles/pj2012162#ref-CR15" id="ref-link-section-d5920135e407">15</a></sup> The methylol, methylene and methylene ether structures were assigned. Several studies on the kinetics of the addition reaction between melamine and formaldehyde in aqueous phase during the initial stage of resin formation have also been explained.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 11" title="Tomita, B. Melamine–formaldehyde resins: molecular species distributions of methylolmelamines and some kinetics of methylolation. J. Poly. Sci. Poly. Chem. Edi. 15, 2347–2365 (1977)." href="/articles/pj2012162#ref-CR11" id="ref-link-section-d5920135e411">11</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 16" title="Gordon, M., Halliwell, A. & Wilson, T. The Chemistry of Polymerization Processes, SCI Monograph No. 20, (Society of Chemical Industry, London, 1965)." href="/articles/pj2012162#ref-CR16" id="ref-link-section-d5920135e414">16</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 17" title="Sato, K. & Naito, T. Studies on melamine resin: kinetics of acid-catalysed condensation of di and trimethylolmelamine. Poly. J. 5, 144–157 (1973)." href="/articles/pj2012162#ref-CR17" id="ref-link-section-d5920135e417">17</a></sup></p><p>Cured resins are, because of their insolubility, more difficult to characterize chemically. Cross-polarization magic angle spinning (CP-MAS) <sup>13</sup>C NMR, CP-MAS <sup>15</sup>N NMR and Fourier transform infrared spectroscopy (FTIR) spectroscopy have already been utilized for the investigation of the chemical reactions that occur during condensation. Curing studies of MF resins by high-resolution solid state <sup>13</sup>C NMR spectra indicate the conversion of free methylo1 groups to methylene linkages throughout curing. However, the methylene ether links overlap with the residual methylol groups, so it is not clear from these spectra whether or not there are many residual unreacted methylol groups.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 13" title="Ebdon, J. R., Hunt, B. J., O’Rourke, W. T. S. & Parkin, J. Characterisation of some melamine-formaldehyde condensates and some cured resins by 1H, 13C and 15N n.m.r. Spectrosc. Br. Poly. J. 20, 327–334 (1988)." href="/articles/pj2012162#ref-CR13" id="ref-link-section-d5920135e429">13</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 8" title="Kandelbauer, A., Wuzella, G., Mahendran, A., Taudes, I. & Widsten, P. Model-free kinetic analysis of melamine-formaldehyde resin cure. Chem. Eng. J. 152, 556–565 (2009)." href="/articles/pj2012162#ref-CR8" id="ref-link-section-d5920135e432">8</a></sup> Information concerning the relative proportions of methylol groups, methylene and methylene ether linkages could be obtained more rapidly from CP-MAS <sup>13</sup>C NMR. FTIR spectroscopy has been shown to have only limited capabilities in this regard due to the high number of slightly different structures in the MF resins which result in very broad and overlapping absorption bands.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 18" title="Braun, D. & Legradic, V. Investigation of the melamine formadehyde reaction products. Ange. Makro. Chemie. 36, 41–55 (1974)." href="/articles/pj2012162#ref-CR18" id="ref-link-section-d5920135e439">18</a></sup> Thermogravimetry/infrared coupling analysis has also been carried out to determine the effluents during the curing process.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 19" title="Devallencourt, C., Saiter, J. M., Fafet, A. & Ubrich, E. Thermogravimetry/fourier transform infrared coupling investigations to study the thermal stability of melamine formaldehyde resin. Thermo. Acta 259, 143–151 (1995)." href="/articles/pj2012162#ref-CR19" id="ref-link-section-d5920135e443">19</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 20" title="Manley, T. R. & Higgs, D. A. Thermal stability of melamine formaldehyde resins. J. Poly. Sci. Symp. 42, 1377–1382 (1973)." href="/articles/pj2012162#ref-CR20" id="ref-link-section-d5920135e446">20</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 21" title="Moore, W. R. & Donnelly, E. Thermal degradation of melamine formaldehyde resins. J. Appl. Chem. 13, 537–543 (1963)." href="/articles/pj2012162#ref-CR21" id="ref-link-section-d5920135e449">21</a></sup> MF polycondensate with high molecular weight and high processing thermostability was prepared with variable melamine: formaldehyde ratios ranging from 1:1.33 to 1:4, which acts as the formaldehyde absorbent by the addition reaction of the hydrogen on the amine groups with the formaldehyde produced by the decomposition of polyoxymethylene under oxygen and heat.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 22" title="Youliang, H., Lin, Y. & Xiaowen, Z. Synthesis of the melamine–formaldehyde polycondensate and its thermal stabilization effect on polyoxymethylene. Polymer 47, 2649–2659 (2006)." href="/articles/pj2012162#ref-CR22" id="ref-link-section-d5920135e453">22</a></sup> Lower crosslinking degree of MF polycondensate was observed at lower formaldehyde ratio (melamine: formaldehyde ratio of 1: 1.33), which was unstable and decomposed during the thermal weight loss analysis. On the other hand, at very high formaldehyde content, the unreacted hydrogen on the MF molecules was not sufficient to have the role as formaldehyde absorbent of polyoxymethylene.</p><p>The MF resin formation consists of two stages: methylolation and condensation. The first attempt to investigate the methylolation and condensation reactions was by Okano and Ogata.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 9" title="Okano, B. M. & Ogata, Y. Kinetics of condensation of melamine with formaldehyde. J. Am. Chem. Soc. 74, 5728–5732 (1952)." href="/articles/pj2012162#ref-CR9" id="ref-link-section-d5920135e460">9</a></sup> In the first step of methylolation reaction, melamine reacts with formaldehyde producing a series of nine distinct methylol melamine from mono-hexamethylol melamine. The second step of condensation reaction leads to the formation of large number of different oligomers containing methylene and methylene ether bridges.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 4" title="Anil, K. & Vimal, K. Modelling and experimental investigation of melamine formaldehyde polymerization. Macromolecules 23, 3729–3736 (1990)." href="/articles/pj2012162#ref-CR4" id="ref-link-section-d5920135e464">4</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 8" title="Kandelbauer, A., Wuzella, G., Mahendran, A., Taudes, I. & Widsten, P. Model-free kinetic analysis of melamine-formaldehyde resin cure. Chem. Eng. J. 152, 556–565 (2009)." href="/articles/pj2012162#ref-CR8" id="ref-link-section-d5920135e467">8</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 10" title="Mijatowic, J., Binder, W. H., Kubel, F. & Kantner, W. Studies on the stability of MF resin solutions: investigations on network formation. Macromol. Symp. 181, 373–382 (2002)." href="/articles/pj2012162#ref-CR10" id="ref-link-section-d5920135e470">10</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 23" title="Vo, D. T., Himmelsbach, M., Haunschmidt, M., Buchberger, W., Schwarzinger, C. & Klambfl, C. W. Improved analysis of melamine-formaldehyde resins by capillary zone electrophoresis-mass spectrometry using ion-trap and quadrupole-time-of-flight mass spectrometers. J. Chromat. A 1213, 83–87 (2008)." href="/articles/pj2012162#ref-CR23" id="ref-link-section-d5920135e473">23</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 24" title="Berge, A. & Mejdell, T. Melamine formaldehyde compounds. The active species in acid catalyzed reactions. Polymer 47, 3249–3256 (2006)." href="/articles/pj2012162#ref-CR24" id="ref-link-section-d5920135e476">24</a></sup></p><p>The ratio of formation of two bridges during condensation reaction depends on the pH of the reaction medium. If the pH is relatively low, 7–8, methylene bridges dominate whereas at high pH values above 9, ether bridges are favored.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 25" title="Naske, R., Dietrich, K., Reinisch, G. & Refler, G. The initial stage of the reaction of melamine with formaldehyde. J. Macromol. Sci. Chem. A 23, 579–596 (1986)." href="/articles/pj2012162#ref-CR25" id="ref-link-section-d5920135e483">25</a></sup> The cure chemistry and the network formation of two acrylic copolymer resins crosslinked with different MF-based crosslinkers have been studied by Bauer and Dickie<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 26" title="Bauer, D. R. & Dickie, R. A. Crosslinking chemistry and network structure in organic coatings. I. Cure of melamine formaldehyde/acrylic copolymer films. J. Poly. Sci. Poly. Phys. Ed. 18, 1997–2014 (1980)." href="/articles/pj2012162#ref-CR26" id="ref-link-section-d5920135e487">26</a></sup> using infrared spectroscopy (IR) spectroscopy, which gives the extent of reaction of the hydroxy and carboxy groups of acrylic copolymer with the methylol group of the MF crosslinker as function of resin composition, melamine type, concentration, cure temperature and cure time. With the data obtained and using a statistical model, effective crosslink density was calculated. The crosslinking chemistry, network formation and degradation of melamine-crosslinked high solids coating have been studied by David.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 27" title="David, B. R. Melamine/formaldehyde crosslinkers: characterization, network formation and crosslink degradation. Prog. Org. Coat. 14, 193–218 (1986)." href="/articles/pj2012162#ref-CR27" id="ref-link-section-d5920135e491">27</a></sup> Author proposed a specific acid-catalyzed mechanism for fully alkylated melamine and a general acid-catalyzed mechanism for partially alkylated melamine. Crosslinking reaction of a highly substituted methylated MF resin with hydroxyl functional polyester analyzed by FTIR has been reported.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 28" title="Wilson, R. C. & Pfohl, W. F. Study of cross-linking reactions of melamine/formaldehyde resin with hydroxyl functional polyester by generalized 2-D infrared spectroscopy. Vibrat. Spect. 23, 13–22 (2000)." href="/articles/pj2012162#ref-CR28" id="ref-link-section-d5920135e495">28</a></sup> Early stage of cure leads to the formation of ether crosslinks before the consumption of all hydroxyl groups and the formation of methylene bridges proceeds through an ether intermediate. FT-Raman spectroscopy in combination with <sup>13</sup>C NMR and liquid chromatography has been used for the elucidation of methylolation and ether–methylene-bridge formation in MF resin.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 29" title="Scheepers, M. L., Gelan, J. M., Carleer, R. A., Adriaensens, P. J. & Vanderzande, D. J. Investigation of melamine-formaldehyde cure by fourier transform Raman spectroscopy. Vibrat. Spect. 6, 55–69 (1993)." href="/articles/pj2012162#ref-CR29" id="ref-link-section-d5920135e502">29</a></sup> Crosslinking of the polyurethane dispersions with MF resin leads to co-condensation reaction has been studied by Mequanint and Sanderson.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 30" title="Mequanint, K. & Sanderson, R. Nano-structure phosphorus-containing polyurethane dispersions: synthesis and crosslinking with melamine formaldehyde resin. Polymer 44, 2631–2639 (2003)." href="/articles/pj2012162#ref-CR30" id="ref-link-section-d5920135e506">30</a></sup></p><p>The reaction mechanisms and the pathways involved in the crosslinking of MF resins and the resulting chemical structures are complex. Cured resins are, because of their insolubility, more difficult to characterize chemically. Even though the curing processes of MF resins are well understood on an empirical basis, there is scope for methods that will provide a more detailed understanding of the chemical reactions that occur during condensation. Research work that has been carried out so far mainly explains the elucidation of methylolmelamines and its reaction path. Only few attempts have been done on the crosslinking reaction mechanism. The crosslinking reaction of MF resin in water that leads to the formation of ether bridge has been explained.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 31" title="Manfred, R., Hartmut, B., Sergey, I., Valery, P., Paul, L. & Primachenko, O. N. The reaction mechanism of the transetherification and crosslinking of melamine resins. Macromol. Symp. 217, 431–443 (2004)." href="/articles/pj2012162#ref-CR31" id="ref-link-section-d5920135e512">31</a></sup> The crosslinking mechanism of fully alkylated and partially alkylated MF resin with catalyst has been studied by Blank.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 32" title="Blank, W. J. Reaction mechanism of amino resin. J. Coat. Techn. 51, 61–70 (1979)." href="/articles/pj2012162#ref-CR32" id="ref-link-section-d5920135e516">32</a></sup> Author found the mechanism by analyzing the volatiles formed during the crosslinking reaction by gas chromatography. Specific acid catalyst was found to be the catalyzing mechanism for fully alkylated MF resin, whereas for the partially alkylated MF resin, the level of formaldehyde content in the reaction volatiles indicated a demethylolation and subsequent catalysis was found to be the crosslinking mechanism. Anderson <i>et al.</i><sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 33" title="Anderson, I. H., Cawley, M. & Steedman, W. Melamine-formaldehyde resins: an examination of some model compound systems. Br. Polym. J. 1, 24–28 (1969)." href="/articles/pj2012162#ref-CR33" id="ref-link-section-d5920135e522">33</a></sup> studied the initial methylolation and the subsequent thermally induced condensation reaction involves the formation of ether links that readily decomposes into methylene link at above 135 °C and this reaction sequence is also accompanied by a demethylolation yielding free amine. Still studies are progressing to find a complete reaction mechanism of MF resin. Even though the reversible demethylolation occurring during the cure reaction of MF resin has been cited with the presence of a catalyst and without the presence of a catalyst, still there is no clear idea at what temperature range demethylolation dominates to the crosslinking reaction and also the temperature where crosslinking reaction dominates to demethylolation for a pure non-alkylated MF resin. Even though many research works have been done so far related to the curing studies of MF, we proposed clarity in the reaction mechanism by thermal and spectroscopic tools that simplify the doubts of MF reaction stages, temperatures and the reaction route. Nowhere in the literature explains the two exothermic peaks observed in differential scanning calorimetry (DSC), even though it is known that the reaction mechanism of MF proceeds in two steps cited by several authors.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 31" title="Manfred, R., Hartmut, B., Sergey, I., Valery, P., Paul, L. & Primachenko, O. N. The reaction mechanism of the transetherification and crosslinking of melamine resins. Macromol. Symp. 217, 431–443 (2004)." href="/articles/pj2012162#ref-CR31" id="ref-link-section-d5920135e526">31</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 32" title="Blank, W. J. Reaction mechanism of amino resin. J. Coat. Techn. 51, 61–70 (1979)." href="/articles/pj2012162#ref-CR32" id="ref-link-section-d5920135e529">32</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 33" title="Anderson, I. H., Cawley, M. & Steedman, W. Melamine-formaldehyde resins: an examination of some model compound systems. Br. Polym. J. 1, 24–28 (1969)." href="/articles/pj2012162#ref-CR33" id="ref-link-section-d5920135e532">33</a></sup> We systematically explains the exact temperature at which the each reaction step is taking place for a non-alkylated MF resin without a catalyst proved by FTIR and consequently a perfect reaction mechanism route has been put forward. The main focus of this paper is to correlate the DSC, spectral and thermal gravimetric analysis (TGA) thermograms of MF resin that are cured thermally for the curing studies. The synthesis and characterization of MF resin are also explained. Characterization techniques such as DSC, FTIR and TGA were used for the studies. Correlating the DSC and TGA thermograms highlights the novelty in the present work.</p></div></div></section><section data-title="Experimental Procedure"><div class="c-article-section" id="Sec2-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="Sec2">Experimental Procedure</h2><div class="c-article-section__content" id="Sec2-content"><h3 class="c-article__sub-heading" id="Sec3">Materials</h3><p>Melamine (Fluka, Ronkonkoma, NY, USA) and formaldehyde solution 35% by weight (Sigma Aldrich, Munich, Germany) were used to synthesize the MF resin. Tetrohydrofuran (THF, Fluka) was used as solvent.</p><h3 class="c-article__sub-heading" id="Sec4">MF resin synthesis</h3><p>MF resin was prepared by the condensation of melamine and formaldehyde. Aqueous solution of formaldehyde (35% by weigh) was used in this study. Before reaction, pH value of the formaldehyde solution was maintained to 8.5–9 by using 1 <span class="u-small-caps">N</span> NaOH solution. 1:3 Molar ratio of melamine/formaldehyde was used for the reaction. Eight grams (0.064 mol) melamine and 15 ml THF were taken in a round-bottomed flask equipped with magnetic stirrer. The reaction bath was kept at 65 °C. Fifteen milliliter (0.192 mol) formaldehyde was added to the above mixture and stirred until melamine is completely dissolved which is recognized by a color change from a white suspension to a clear solution. Then the reaction was continued for further 15 min. The clear solution was cool down. Cooling was carried out at room temperature for 30 min. Solvent was removed by rotary evaporator and further by heating at 50 °C under vacuum overnight. The resulting uncured powder sample was used for further studies.</p><h3 class="c-article__sub-heading" id="Sec5">Preparation of partially and fully cured samples</h3><p>To study the structure at different crosslinking stages, three methylolmelamine samples, 1 g each, were heated in a convection oven from room temperature to 160, 170, and 195 °C at a heating rate of 5 °C min<sup>−1</sup>. Once the corresponding temperatures have been reach each sample has been taken out from the oven, air dried to room temperature, and used for the FTIR study.</p><h3 class="c-article__sub-heading" id="Sec6">Characterization methods</h3><h4 class="c-article__sub-heading c-article__sub-heading--small" id="Sec7">Differential scanning calorimetry</h4><p>DSC analysis was carried out in a NETZSCH (Selb, Germany) DSC 204 F1 instrument to study the cure properties of MF resin. Aluminum pans were used as the crucibles for the DSC run. Sample size of between 5–10 mg was used for the analysis. Dynamic scans were made from 50 to 200 °C at a constant heating rate. Heating rates of 2, 5, 10, 15 and 20 °C min<sup>−1</sup> were used to study the curing properties of MF resin. For the DSC run, aluminum pans are pierced in order to evaporate any effluents coming out during the scan. All DSC runs were carried out in an inert atmosphere of N<sub>2</sub>.</p><h4 class="c-article__sub-heading c-article__sub-heading--small" id="Sec8">Fourier transform infrared spectroscopy</h4><p>FTIR studies were performed in a Thermo Scientific (Barrington, IL, USA) Nicolet IS10 spectrophotometer. The samples were scanned in the form of KBr pellets containing 1 mg of the sample and 100 mg of KBr powder. Spectrum was recorded in the wavenumber range of 4000–500 cm<sup>−1</sup> by signal averaging of 32 scans at a resolution of 4 cm<sup>−1</sup>. The spectra were recorded as percentage transmittance versus wavenumber.</p><h4 class="c-article__sub-heading c-article__sub-heading--small" id="Sec9">Thermogravimetric analysis</h4><p>Thermogravimetric analysis was performed in a Netzsch STA 409 thermobalance apparatus. Dynamic temperature scan was performed from 50 to 600 °C at a constant heating rate of 5 °C min<sup>−1</sup>. Analysis was carried out in an inert atmosphere of nitrogen gas with a flow rate of 20 ml min<sup>−1</sup>. About 15–25 mg of the sample was placed in a ceramic crucible to perform the TGA analysis.</p></div></div></section><section data-title="Results and discussion"><div class="c-article-section" id="Sec10-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="Sec10">Results and discussion</h2><div class="c-article-section__content" id="Sec10-content"><h3 class="c-article__sub-heading" id="Sec11">Polymerization and formulation of MF resin</h3><p>Polymerization (curing) of melamine to formaldehyde occurs in two stages. The first step of methylolation is the addition reaction of formaldehyde to melamine that can be carried out in an aqueous phase under neutral or basic conditions or under solvent medium.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 34" title="Dawbarn, M., Ebdon, J. R. & Hewitt, S. J. Examination of some melamine formaldehyde adduct by C13 nuclear magnetic resonance. Polymer 19, 1309–1312 (1978)." href="/articles/pj2012162#ref-CR34" id="ref-link-section-d5920135e623">34</a></sup> The second stage of curing mainly consists of two types of condensation reactions leading to the formation of methylene and methylene ether bridges that can be cured either thermally or under acidic/alkaline conditions.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 21" title="Moore, W. R. & Donnelly, E. Thermal degradation of melamine formaldehyde resins. J. Appl. Chem. 13, 537–543 (1963)." href="/articles/pj2012162#ref-CR21" id="ref-link-section-d5920135e627">21</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 23" title="Vo, D. T., Himmelsbach, M., Haunschmidt, M., Buchberger, W., Schwarzinger, C. & Klambfl, C. W. Improved analysis of melamine-formaldehyde resins by capillary zone electrophoresis-mass spectrometry using ion-trap and quadrupole-time-of-flight mass spectrometers. J. Chromat. A 1213, 83–87 (2008)." href="/articles/pj2012162#ref-CR23" id="ref-link-section-d5920135e630">23</a>, <a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 30" title="Mequanint, K. & Sanderson, R. Nano-structure phosphorus-containing polyurethane dispersions: synthesis and crosslinking with melamine formaldehyde resin. Polymer 44, 2631–2639 (2003)." href="/articles/pj2012162#ref-CR30" id="ref-link-section-d5920135e633">30</a></sup> During curing, chain extension and crosslinking takes place to form an insoluble and infusible three-dimensional network. In this study, stoichiometric ratio of melamine: formaldehyde was chosen as 1:3. The first step of methylolation was carried out in solvent THF. Resulted methylolmelamine was cured thermally at 195 °C for 45 min.</p><h3 class="c-article__sub-heading" id="Sec12">Curing studies</h3><p>FTIR analysis was carried out to identify the first stage and the second stage reaction completion. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/pj2012162#Fig1">Figure 1</a> shows the FTIR spectra of melamine, methylolmelamine and the cured resin. The spectra of methylolmelamine (<a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/pj2012162#Fig1">Figure 1</a>) show absorbances at 3330 cm<sup>−1</sup> and 3190 cm<sup>−1</sup> correspond to the stretching vibrations of secondary amine. The peak at 2960 cm<sup>−1</sup> is due the C–H stretching vibration of methylol group. –C=N ring vibration is observed at 1530 cm<sup>−1</sup>. The peak at 1456 and 1388 cm<sup>−1</sup> corresponds to the methylene C–H bending vibrations. The absorbance at 1182 cm<sup>−1</sup> corresponds to aliphatic C–N vibration. The absorbance at 1110 cm<sup>−1</sup> corresponds to C–O stretching vibration. The peak at 1060 cm<sup>−1</sup> corresponds to the stretching vibration of ether group. The absorptions at 994 and 590 cm<sup>−1</sup> correspond to C–H out of plane deformations. Bending vibration of triazine ring was found at 810 cm<sup>−1</sup>. From this spectrum of MF resin, it is understood that the melamine has reacted to methylol groups and there is no residual melamine and formaldehyde remains. Spectra of cured MF (<a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/pj2012162#Fig1">Figure 1</a>) show the N–H stretching frequency of secondary amine at 3416 cm<sup>−1</sup>. Methylene C–H bending vibration appeared at 1456 cm<sup>−1</sup>. And there occurs a generation of new strong peak at 2338 cm<sup>−1</sup> that corresponds to the stretching vibration of bridged CH<sub>2</sub> group, which gave a strong evidence for methylene bridge formation.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 15" title="Sing, M. & Kumar, M. Preparation and characterisation of melamine-formaldehyde-polyvinylpyrrolidone polymer resin for better industrial uses over melamine resin. J. Appl. Poly. Sci. 114, 1870–1878 (2009)." href="/articles/pj2012162#ref-CR15" id="ref-link-section-d5920135e685">15</a></sup> And also there is a decrease in the intensity of the peaks at 1556 and 1437 cm<sup>−1</sup> that corresponds to the methylene bending vibrations. This decrease in intensity may possibly due to the extent of crosslinking. From this FTIR interpretation, it was confirmed that the melamine has reacted and crosslinked during the thermal curing process. IR spectral data of the methylolmelamine and cured MF are compiled in <a data-track="click" data-track-label="link" data-track-action="table anchor" href="/articles/pj2012162#Tab1">Table 1</a>.</p><div class="c-article-section__figure js-c-reading-companion-figures-item" data-test="figure" data-container-section="figure" id="figure-1" data-title="Figure 1"><figure><figcaption><b id="Fig1" class="c-article-section__figure-caption" data-test="figure-caption-text">Figure 1</b></figcaption><div class="c-article-section__figure-content"><div class="c-article-section__figure-item"><a class="c-article-section__figure-link" data-test="img-link" data-track="click" data-track-label="image" data-track-action="view figure" href="/articles/pj2012162/figures/1" rel="nofollow"><picture><source type="image/webp" srcset="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fig1_HTML.jpg?as=webp"><img aria-describedby="Fig1" src="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fig1_HTML.jpg" alt="figure 1" loading="lazy" width="405" height="271"></picture></a></div><div class="c-article-section__figure-description" data-test="bottom-caption" id="figure-1-desc"><p>FTIR spectra of melamine, methylolmelamine and cured MF. A full color version of this figure is available at <i>Polymer Journal</i> online.</p></div></div><div class="u-text-right u-hide-print"><a class="c-article__pill-button" data-test="article-link" data-track="click" data-track-label="button" data-track-action="view figure" href="/articles/pj2012162/figures/1" data-track-dest="link:Figure1 Full size image" aria-label="Full size image figure 1" rel="nofollow"><span>Full size image</span><svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-chevron-right-small"></use></svg></a></div></figure></div><div class="c-article-table" data-test="inline-table" data-container-section="table" id="table-1"><figure><figcaption class="c-article-table__figcaption"><b id="Tab1" data-test="table-caption">Table 1 IR spectral data of melamine, methylolmelamine and MF resin at variable temperatures</b></figcaption><div class="u-text-right u-hide-print"><a class="c-article__pill-button" data-test="table-link" data-track="click" data-track-action="view table" data-track-label="button" rel="nofollow" href="/articles/pj2012162/tables/1" aria-label="Full size table 1"><span>Full size table</span><svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-chevron-right-small"></use></svg></a></div></figure></div><p>To study the curing of MF resins, DSC analysis was carried out by performing dynamic scans were made from 50 to 200 °C at variable heating rates of 2, 5, 10, 15 and 20 °C min<sup>−1</sup>.</p><p><a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/pj2012162#Fig2">Figure 2</a> shows the DSC thermograms of an MF resin at different heating rates. The initial increase in the exothermal enthalpy indicates the start of the resin crosslinking. After reaching a maximum, the enthalpy decreases revealing some kind of reaction completion and then again the enthalpy increases and then decreases until the resin crosslinking reaction completes. Hence, the DSC thermograms exhibit two exotherms, indication of two steps of reaction occurring during the thermal curing process. Indication of two-step reaction is further supported by FTIR analysis, which will be discussed later.</p><div class="c-article-section__figure js-c-reading-companion-figures-item" data-test="figure" data-container-section="figure" id="figure-2" data-title="Figure 2"><figure><figcaption><b id="Fig2" class="c-article-section__figure-caption" data-test="figure-caption-text">Figure 2</b></figcaption><div class="c-article-section__figure-content"><div class="c-article-section__figure-item"><a class="c-article-section__figure-link" data-test="img-link" data-track="click" data-track-label="image" data-track-action="view figure" href="/articles/pj2012162/figures/2" rel="nofollow"><picture><source type="image/webp" srcset="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fig2_HTML.jpg?as=webp"><img aria-describedby="Fig2" src="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fig2_HTML.jpg" alt="figure 2" loading="lazy" width="385" height="264"></picture></a></div><div class="c-article-section__figure-description" data-test="bottom-caption" id="figure-2-desc"><p>DSC thermograms of MF resin at different heating rates. A full color version of this figure is available at <i>Polymer Journal</i> online.</p></div></div><div class="u-text-right u-hide-print"><a class="c-article__pill-button" data-test="article-link" data-track="click" data-track-label="button" data-track-action="view figure" href="/articles/pj2012162/figures/2" data-track-dest="link:Figure2 Full size image" aria-label="Full size image figure 2" rel="nofollow"><span>Full size image</span><svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-chevron-right-small"></use></svg></a></div></figure></div><p><a data-track="click" data-track-label="link" data-track-action="table anchor" href="/articles/pj2012162#Tab2">Table 2</a> shows the peak temperatures with variable heating rates for the MF resin. As the heating rate increased, the two peak temperatures of MF resin also increased indicating a slower cure rate of the resin. The evolution of two exothermic peaks implies that the crosslinking of melamine to formaldehyde proceeds in a two-step reaction process. The first exotherm may be attributed to the reversible reaction of methylolmelamine whereas the second exotherm corresponds to the crosslinking of methylol to methylene bridges during the thermal curing process.</p><div class="c-article-table" data-test="inline-table" data-container-section="table" id="table-2"><figure><figcaption class="c-article-table__figcaption"><b id="Tab2" data-test="table-caption">Table 2 Variation of peak temperatures with heating rates</b></figcaption><div class="u-text-right u-hide-print"><a class="c-article__pill-button" data-test="table-link" data-track="click" data-track-action="view table" data-track-label="button" rel="nofollow" href="/articles/pj2012162/tables/2" aria-label="Full size table 2"><span>Full size table</span><svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-chevron-right-small"></use></svg></a></div></figure></div><p>To support the DSC investigation for evolution of two exotherms observed, FTIR studies were carried out for the samples cured at two different temperatures 160 °C and 170 °C, respectively. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/pj2012162#Fig3">Figure 3</a> shows the spectral characterization of MF at two temperatures. Spectral characterization of MF at 160 °C (<a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/pj2012162#Fig3">Figure 3</a>) shows several distinct peaks. The spectral frequencies between 3464 and 3125 cm<sup>−1</sup> corresponds to the primary amine groups of melamine. For comparison, FTIR spectrum of melamine is also shown in <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/pj2012162#Fig3">Figure 3</a>. Hence, compiling DSC and FTIR studies it suggests that at temperature range from 140 to 160 °C, to some extent the reaction proceeds in a reversible way by converting methylol groups to melamine and thus from the IR data; it is also confirmed that there is no crosslinking reaction taking place at this temperature range, rather, the reverse reaction is taking place. Rest of the absorptions remains the same as methylolmelamine.</p><div class="c-article-section__figure js-c-reading-companion-figures-item" data-test="figure" data-container-section="figure" id="figure-3" data-title="Figure 3"><figure><figcaption><b id="Fig3" class="c-article-section__figure-caption" data-test="figure-caption-text">Figure 3</b></figcaption><div class="c-article-section__figure-content"><div class="c-article-section__figure-item"><a class="c-article-section__figure-link" data-test="img-link" data-track="click" data-track-label="image" data-track-action="view figure" href="/articles/pj2012162/figures/3" rel="nofollow"><picture><source type="image/webp" srcset="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fig3_HTML.jpg?as=webp"><img aria-describedby="Fig3" src="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fig3_HTML.jpg" alt="figure 3" loading="lazy" width="409" height="280"></picture></a></div><div class="c-article-section__figure-description" data-test="bottom-caption" id="figure-3-desc"><p>FTIR spectra of melamine, MF resin at 160°C, and MF resin at 170°C. A full color version of this figure is available at <i>Polymer Journal</i> online.</p></div></div><div class="u-text-right u-hide-print"><a class="c-article__pill-button" data-test="article-link" data-track="click" data-track-label="button" data-track-action="view figure" href="/articles/pj2012162/figures/3" data-track-dest="link:Figure3 Full size image" aria-label="Full size image figure 3" rel="nofollow"><span>Full size image</span><svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-chevron-right-small"></use></svg></a></div></figure></div><p>Spectra of MF at 170 °C are shown in <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/pj2012162#Fig3">Figure 3</a>. It shows the absorbance is the same as methylolmelamine (<a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/pj2012162#Fig1">Figure 1</a>). Spectral data of MF at two different temperatures are also compiled in <a data-track="click" data-track-label="link" data-track-action="table anchor" href="/articles/pj2012162#Tab1">Table 1</a>. From this IR study at two different temperatures, we attribute the first exotherm observed in DSC to the reverse demethylolation reaction and the second exotherm to the crosslinking reaction of MF resin.</p><p>It is evident that the crosslinking mechanism of MF proceeds in two different steps as indicated by DSC analysis. Although reported mechanism for the condensation step for the curing of MF is suggested to involve methylene and ether bridges as intermediate condensation products and these intermediates transform to desired insoluble and infusible MF resins during the final curing process.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 35" title="Pizzi, A. Handbook of Adhesive Technology 2nd edn (eds Pizzi and Mittal) Ch. 32 653–680 (Marcel Dekker, France, Inc., 2003)." href="/articles/pj2012162#ref-CR35" id="ref-link-section-d5920135e1612">35</a></sup> However, this mechanism cannot explain the presence of melamine as an intermediate product as confirmed by the presence of –NH<sub>2</sub> groups in the FTIR spectrum for sample heated from 140 to 160 °C and disappearance of these groups from the spectrum of the samples heated above 160 °C. Therefore, based on the DSC and the FTIR results, which are in agreement, we propose a modified mechanism as discussed in the following below.</p><h4 class="c-article__sub-heading c-article__sub-heading--small" id="Sec13">Methylolation step</h4><p>This step is well studied and involves direct reaction between melamine and formaldehyde to form methylolamine as follows.</p> <div style="width:300px; max-width:100%;" class="c-article-section__illustration-center c-article-section__illustration u-clearfix" data-test="illustration" id="i2"><div class="c-article-section__figure c-article-section__figure--1-border"><picture><source type="image/webp" srcset="//media.springernature.com/w300/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figd_HTML.jpg?as=webp"><img class="c-article-section__figure--1-border-image" alt="" width="300" src="//media.springernature.com/w300/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figd_HTML.jpg"></picture></div></div><h4 class="c-article__sub-heading c-article__sub-heading--small" id="Sec14">Condensation step</h4><p>This step is more complex and involves multiple reactions that lead to intermediate ether-linkage-containing compounds. These ether linkages are transformed into methylene linkages by the elimination of formaldehyde as described by <a data-track="click" data-track-label="link" data-track-action="" href="/articles/pj2012162#Sch1">Scheme 1</a>. However, we suggest the existence of another reaction that leads to the formation of the methylene bridges in the final cured product through reaction between methylolamine formed in the methylolation reaction and melamine.</p><p>As discussed in the previous sections, melamine is formed by the decomposition of methylolamine at a temperature above 140 °C as shown in <a data-track="click" data-track-label="link" data-track-action="" href="/articles/pj2012162#Sch2">Scheme 2</a>.</p><p>This reaction step is confirmed by the presence of the -NH<sub>2</sub> groups in the FTIR spectrum for the partially cured sample (T<160 °C).</p><h4 class="c-article__sub-heading c-article__sub-heading--small" id="Sec15">Correlating DSC and TGA analysis</h4><p><a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/pj2012162#Fig4">Figure 4</a> shows the TGA and the DSC thermograms of MF resin in the temperature range from 50 to 600 °C. We can define four temperature ranges where the weight losses appeared, from 100 to 180, 180 to 350, 350 to 390 and 390 to 600 °C, respectively. Correspondingly two exotherms were observed in the DSC thermograms. The first exotherm in the temperature region 100–180 °C corresponds to the curing reaction of MF resin splits into two, as in the DSC study, which gave support for the cure reaction, and also the weight loss is related to the thermal curing process. Corresponding 12.36% weight loss is due to the evaporation of water during the condensation process. Of total 12.36% weight loss, 7.1% weight loss corresponds to water elimination due to the self-condensation of methylol groups, leading to ether bridge formation as per the reaction occurring in 140–160 °C temperature range, and the rest of 5.26% weight loss is also due to water elimination during the condensation reaction between melamine and the methylol group, which leads to the methylene bridge as per the curing reaction occurring at temperature >160 °C, as shown in <a data-track="click" data-track-label="link" data-track-action="" href="/articles/pj2012162#Sch1">Scheme 1</a>. The weight % was calculated based on the 1:3 melamine: formaldehyde mole ratios.</p><div class="c-article-section__figure js-c-reading-companion-figures-item" data-test="figure" data-container-section="figure" id="figure-4" data-title="Figure 4"><figure><figcaption><b id="Fig4" class="c-article-section__figure-caption" data-test="figure-caption-text">Figure 4</b></figcaption><div class="c-article-section__figure-content"><div class="c-article-section__figure-item"><a class="c-article-section__figure-link" data-test="img-link" data-track="click" data-track-label="image" data-track-action="view figure" href="/articles/pj2012162/figures/4" rel="nofollow"><picture><source type="image/webp" srcset="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fig4_HTML.jpg?as=webp"><img aria-describedby="Fig4" src="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fig4_HTML.jpg" alt="figure 4" loading="lazy" width="403" height="287"></picture></a></div><div class="c-article-section__figure-description" data-test="bottom-caption" id="figure-4-desc"><p>TGA and DSC thermograms of MF resin. A full color version of this figure is available at <i>Polymer Journal</i> online.</p></div></div><div class="u-text-right u-hide-print"><a class="c-article__pill-button" data-test="article-link" data-track="click" data-track-label="button" data-track-action="view figure" href="/articles/pj2012162/figures/4" data-track-dest="link:Figure4 Full size image" aria-label="Full size image figure 4" rel="nofollow"><span>Full size image</span><svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-chevron-right-small"></use></svg></a></div></figure></div><p>Weight loss of 12.8% occurs in the temperature range of 180–350 °C corresponds to the elimination of formaldehyde from the ether bridge forming methylene bridge as shown below:</p> <div style="width:300px; max-width:100%;" class="c-article-section__illustration-center c-article-section__illustration u-clearfix" data-test="illustration" id="i3"><div class="c-article-section__figure c-article-section__figure--1-border"><picture><source type="image/webp" srcset="//media.springernature.com/w300/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fige_HTML.gif?as=webp"><img class="c-article-section__figure--1-border-image" alt="" width="300" src="//media.springernature.com/w300/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Fige_HTML.gif"></picture></div></div><p>Third, weight loss of 22.8% observed in the temperature range of 350–390 °C is attributed to the breakdown of methyelene bridges.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 20" title="Manley, T. R. & Higgs, D. A. Thermal stability of melamine formaldehyde resins. J. Poly. Sci. Symp. 42, 1377–1382 (1973)." href="/articles/pj2012162#ref-CR20" id="ref-link-section-d5920135e1709">20</a></sup> Correspondingly, DSC thermogram shows an exothermic peak. Possible reaction mechanism of the breakage of methylene bridge is shown below:</p> <div style="width:300px; max-width:100%;" class="c-article-section__illustration-center c-article-section__illustration u-clearfix" data-test="illustration" id="i4"><div class="c-article-section__figure c-article-section__figure--1-border"><picture><source type="image/webp" srcset="//media.springernature.com/w300/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figf_HTML.gif?as=webp"><img class="c-article-section__figure--1-border-image" alt="" width="300" src="//media.springernature.com/w300/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figf_HTML.gif"></picture></div></div> <div style="width:300px; max-width:100%;" class="c-article-section__illustration-center c-article-section__illustration u-clearfix" data-test="illustration" id="i5"><div class="c-article-section__figure c-article-section__figure--1-border"><picture><source type="image/webp" srcset="//media.springernature.com/w300/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figg_HTML.gif?as=webp"><img class="c-article-section__figure--1-border-image" alt="" width="300" src="//media.springernature.com/w300/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figg_HTML.gif"></picture></div></div><p>CH<sub>2</sub>NH fragment dimerizes to azomethane, which will dimerize to ethane as follows:</p> <div style="width:300px; max-width:100%;" class="c-article-section__illustration-center c-article-section__illustration u-clearfix" data-test="illustration" id="i6"><div class="c-article-section__figure c-article-section__figure--1-border"><picture><source type="image/webp" srcset="//media.springernature.com/w300/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figh_HTML.gif?as=webp"><img class="c-article-section__figure--1-border-image" alt="" width="300" src="//media.springernature.com/w300/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figh_HTML.gif"></picture></div></div><p>Weight loss beyond 390 °C is attributed to the thermal degradation of the triazine ring, and it is assumed that MF resin progressively deaminates to form HCN.<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 19" title="Devallencourt, C., Saiter, J. M., Fafet, A. & Ubrich, E. Thermogravimetry/fourier transform infrared coupling investigations to study the thermal stability of melamine formaldehyde resin. Thermo. Acta 259, 143–151 (1995)." href="/articles/pj2012162#ref-CR19" id="ref-link-section-d5920135e1755">19</a></sup></p></div></div></section><section data-title="Conclusions"><div class="c-article-section" id="Sec16-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="Sec16">Conclusions</h2><div class="c-article-section__content" id="Sec16-content"><p>The curing mechanism of MF resin was explained by both thermal and spectroscopic studies. DSC thermogram exhibited two exotherms which gave evidence of two-stage curing process. Subsequent FTIR studies at two exothermic peak temperatures observed in DSC reveal the two-stage crosslinking reaction mechanism. The first step of thermal curing at temperature range of 140–160 °C is the reverse reaction of methylol groups to melamine and second step occurring at temperature >160 °C is the crosslinking reaction. Hence, by the mutual agreement of DSC and FTIR studies, a possible reaction route was derived for the thermal curing process. The TGA characterization clearly shows four successive mass losses in the temperature range of 50–600 °C, which is correlated to the DSC thermogram. Correlation of the DSC and TGA clearly explains the weight loss during the curing process due to the evaporation of water and formaldehyde. As in the DSC study, DSC–TGA thermogram supports the two-step process of the cure reaction by exhibiting two peaks in the same temperature region. First peak at 160 °C corresponds to the weight loss due to the elimination of formaldehyde due to the reverse reaction of MF resin, and the second peak corresponds to water elimination due to the condensation reaction. Methylene bridges are stable up to 350 °C, and the thermal degradation of triazine ring begins at 400 °C. </p><div class="c-article-section__figure c-article-section__figure--no-border" data-test="figure" data-container-section="figure" id="scheme-1"><figure><div class="c-article-section__figure-content" id="Sch1"><div class="c-article-section__figure-item"><div class="c-article-section__figure-content"><picture><source type="image/webp" srcset="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figb_HTML.jpg?as=webp"><img aria-describedby="Sch1" src="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figb_HTML.jpg" alt="scheme 1" loading="lazy" width="685" height="492"></picture></div></div><div class="c-article-section__figure-description" data-test="bottom-caption" id="scheme-1-desc"><p>Reaction mechanism of thermal curing of MF resin.</p></div></div></figure></div><div class="c-article-section__figure c-article-section__figure--no-border" data-test="figure" data-container-section="figure" id="scheme-2"><figure><div class="c-article-section__figure-content" id="Sch2"><div class="c-article-section__figure-item"><div class="c-article-section__figure-content"><picture><source type="image/webp" srcset="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figc_HTML.jpg?as=webp"><img aria-describedby="Sch2" src="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fpj.2012.162/MediaObjects/41428_2013_Article_BFpj2012162_Figc_HTML.jpg" alt="scheme 2" loading="lazy" width="422" height="95"></picture></div></div><div class="c-article-section__figure-description" data-test="bottom-caption" id="scheme-2-desc"><p>Formation of melamine by decomposition of methylolamine.</p></div></div></figure></div></div></div></section> </div> <div class="u-mt-32"> <div id="MagazineFulltextArticleBodySuffix"><section aria-labelledby="Bib1" data-title="References"><div class="c-article-section" id="Bib1-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="Bib1">References</h2><div class="c-article-section__content" id="Bib1-content"><div data-container-section="references"><ol class="c-article-references" data-track-component="outbound reference" data-track-context="references section"><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="1"><p class="c-article-references__text" id="ref-CR1">Bajia, S., Sharma, R. & Bajia, B. Solid-state microwave synthesis of melamine formaldehyde resin. <i>J. Chem.</i> <b>6</b>, 120–124 (2009).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BD1MXnslCqtw%3D%3D" aria-label="CAS reference 1">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 1" href="http://scholar.google.com/scholar_lookup?&title=Solid-state%20microwave%20synthesis%20of%20melamine%20formaldehyde%20resin&journal=J.%20Chem.&volume=6&pages=120-124&publication_year=2009&author=Bajia%2CS&author=Sharma%2CR&author=Bajia%2CB"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="2"><p class="c-article-references__text" id="ref-CR2">Park, B. -D. & Jeong, H. -W. Cure kinetics of melamine-formaldehyde resin/clay/cellulose nanocomposites. <i>J. Ind. Eng. Chem.</i> <b>16</b>, 375–379 (2010).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/j.jiec.2010.01.035" data-track-item_id="10.1016/j.jiec.2010.01.035" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2Fj.jiec.2010.01.035" aria-label="Article reference 2" data-doi="10.1016/j.jiec.2010.01.035">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BC3cXmtFymtLs%3D" aria-label="CAS reference 2">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 2" href="http://scholar.google.com/scholar_lookup?&title=Cure%20kinetics%20of%20melamine-formaldehyde%20resin%2Fclay%2Fcellulose%20nanocomposites&journal=J.%20Ind.%20Eng.%20Chem.&doi=10.1016%2Fj.jiec.2010.01.035&volume=16&pages=375-379&publication_year=2010&author=Park%2CB-D&author=Jeong%2CH-W"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="3"><p class="c-article-references__text" id="ref-CR3">Dipak, K. R., Amit, J. P. & Bhavi, N. N. A Study on composites from casein modified melamine formaldehyde resin. <i>Poly. Plast. Tech. Eng.</i> <b>45</b>, 293–299 (2006).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1080/03602550500371562" data-track-item_id="10.1080/03602550500371562" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1080%2F03602550500371562" aria-label="Article reference 3" data-doi="10.1080/03602550500371562">Article</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 3" href="http://scholar.google.com/scholar_lookup?&title=A%20Study%20on%20composites%20from%20casein%20modified%20melamine%20formaldehyde%20resin&journal=Poly.%20Plast.%20Tech.%20Eng.&doi=10.1080%2F03602550500371562&volume=45&pages=293-299&publication_year=2006&author=Dipak%2CKR&author=Amit%2CJP&author=Bhavi%2CNN"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="4"><p class="c-article-references__text" id="ref-CR4">Anil, K. & Vimal, K. Modelling and experimental investigation of melamine formaldehyde polymerization. <i>Macromolecules</i> <b>23</b>, 3729–3736 (1990).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1021/ma00218a003" data-track-item_id="10.1021/ma00218a003" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1021%2Fma00218a003" aria-label="Article reference 4" data-doi="10.1021/ma00218a003">Article</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 4" href="http://scholar.google.com/scholar_lookup?&title=Modelling%20and%20experimental%20investigation%20of%20melamine%20formaldehyde%20polymerization&journal=Macromolecules&doi=10.1021%2Fma00218a003&volume=23&pages=3729-3736&publication_year=1990&author=Anil%2CK&author=Vimal%2CK"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="5"><p class="c-article-references__text" id="ref-CR5">El-Sayed, W. S., El-Baz, A. F. & Othman, A. M. Biodegradation of melamine formaldehyde by micrococcus sp. strain MF-1 isolated from aminoplastic waste water effluent. <i>Int. Biodeteriorat. Biodegradat.</i> <b>57</b>, 75–81 (2006).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/j.ibiod.2005.11.006" data-track-item_id="10.1016/j.ibiod.2005.11.006" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2Fj.ibiod.2005.11.006" aria-label="Article reference 5" data-doi="10.1016/j.ibiod.2005.11.006">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BD28XitVaks7w%3D" aria-label="CAS reference 5">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 5" href="http://scholar.google.com/scholar_lookup?&title=Biodegradation%20of%20melamine%20formaldehyde%20by%20micrococcus%20sp.%20strain%20MF-1%20isolated%20from%20aminoplastic%20waste%20water%20effluent&journal=Int.%20Biodeteriorat.%20Biodegradat.&doi=10.1016%2Fj.ibiod.2005.11.006&volume=57&pages=75-81&publication_year=2006&author=El-Sayed%2CWS&author=El-Baz%2CAF&author=Othman%2CAM"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="6"><p class="c-article-references__text" id="ref-CR6">Wohnsiedler, H. P. Polymerisation in melamine-formaldehyde molded resins. <i>Ind. Eng. Chem.</i> <b>45</b>, 2307–2311 (1953).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1021/ie50526a045" data-track-item_id="10.1021/ie50526a045" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1021%2Fie50526a045" aria-label="Article reference 6" data-doi="10.1021/ie50526a045">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaG2cXpsVyq" aria-label="CAS reference 6">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 6" href="http://scholar.google.com/scholar_lookup?&title=Polymerisation%20in%20melamine-formaldehyde%20molded%20resins&journal=Ind.%20Eng.%20Chem.&doi=10.1021%2Fie50526a045&volume=45&pages=2307-2311&publication_year=1953&author=Wohnsiedler%2CHP"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="7"><p class="c-article-references__text" id="ref-CR7">Kandelbauer, A., Wuzella, G., Mahendran, A., Taudes, I. & Widsten, P. Using isoconventional kinetic analysis of liquid melamine-formaldehyde resin curing to predict laminate surface properties. <i>J. Appl. Polym. Sci.</i> <b>113</b>, 2649–2660 (2009).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1002/app.30294" data-track-item_id="10.1002/app.30294" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1002%2Fapp.30294" aria-label="Article reference 7" data-doi="10.1002/app.30294">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BD1MXmt1agt7g%3D" aria-label="CAS reference 7">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 7" href="http://scholar.google.com/scholar_lookup?&title=Using%20isoconventional%20kinetic%20analysis%20of%20liquid%20melamine-formaldehyde%20resin%20curing%20to%20predict%20laminate%20surface%20properties&journal=J.%20Appl.%20Polym.%20Sci.&doi=10.1002%2Fapp.30294&volume=113&pages=2649-2660&publication_year=2009&author=Kandelbauer%2CA&author=Wuzella%2CG&author=Mahendran%2CA&author=Taudes%2CI&author=Widsten%2CP"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="8"><p class="c-article-references__text" id="ref-CR8">Kandelbauer, A., Wuzella, G., Mahendran, A., Taudes, I. & Widsten, P. Model-free kinetic analysis of melamine-formaldehyde resin cure. <i>Chem. Eng. J.</i> <b>152</b>, 556–565 (2009).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/j.cej.2009.05.027" data-track-item_id="10.1016/j.cej.2009.05.027" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2Fj.cej.2009.05.027" aria-label="Article reference 8" data-doi="10.1016/j.cej.2009.05.027">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BD1MXosVWrtbo%3D" aria-label="CAS reference 8">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 8" href="http://scholar.google.com/scholar_lookup?&title=Model-free%20kinetic%20analysis%20of%20melamine-formaldehyde%20resin%20cure&journal=Chem.%20Eng.%20J.&doi=10.1016%2Fj.cej.2009.05.027&volume=152&pages=556-565&publication_year=2009&author=Kandelbauer%2CA&author=Wuzella%2CG&author=Mahendran%2CA&author=Taudes%2CI&author=Widsten%2CP"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="9"><p class="c-article-references__text" id="ref-CR9">Okano, B. M. & Ogata, Y. Kinetics of condensation of melamine with formaldehyde. <i>J. Am. Chem. Soc.</i> <b>74</b>, 5728–5732 (1952).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1021/ja01142a047" data-track-item_id="10.1021/ja01142a047" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1021%2Fja01142a047" aria-label="Article reference 9" data-doi="10.1021/ja01142a047">Article</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 9" href="http://scholar.google.com/scholar_lookup?&title=Kinetics%20of%20condensation%20of%20melamine%20with%20formaldehyde&journal=J.%20Am.%20Chem.%20Soc.&doi=10.1021%2Fja01142a047&volume=74&pages=5728-5732&publication_year=1952&author=Okano%2CBM&author=Ogata%2CY"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="10"><p class="c-article-references__text" id="ref-CR10">Mijatowic, J., Binder, W. H., Kubel, F. & Kantner, W. Studies on the stability of MF resin solutions: investigations on network formation. <i>Macromol. Symp.</i> <b>181</b>, 373–382 (2002).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1002/1521-3900(200205)181:1<373::AID-MASY373>3.0.CO;2-J" data-track-item_id="10.1002/1521-3900(200205)181:1<373::AID-MASY373>3.0.CO;2-J" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1002%2F1521-3900%28200205%29181%3A1%3C373%3A%3AAID-MASY373%3E3.0.CO%3B2-J" aria-label="Article reference 10" data-doi="10.1002/1521-3900(200205)181:1<373::AID-MASY373>3.0.CO;2-J">Article</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 10" href="http://scholar.google.com/scholar_lookup?&title=Studies%20on%20the%20stability%20of%20MF%20resin%20solutions%3A%20investigations%20on%20network%20formation&journal=Macromol.%20Symp.&doi=10.1002%2F1521-3900%28200205%29181%3A1%3C373%3A%3AAID-MASY373%3E3.0.CO%3B2-J&volume=181&pages=373-382&publication_year=2002&author=Mijatowic%2CJ&author=Binder%2CWH&author=Kubel%2CF&author=Kantner%2CW"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="11"><p class="c-article-references__text" id="ref-CR11">Tomita, B. Melamine–formaldehyde resins: molecular species distributions of methylolmelamines and some kinetics of methylolation. <i>J. Poly. Sci. Poly. Chem. Edi.</i> <b>15</b>, 2347–2365 (1977).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1002/pol.1977.170151005" data-track-item_id="10.1002/pol.1977.170151005" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1002%2Fpol.1977.170151005" aria-label="Article reference 11" data-doi="10.1002/pol.1977.170151005">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaE2sXls1yltL8%3D" aria-label="CAS reference 11">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 11" href="http://scholar.google.com/scholar_lookup?&title=Melamine%E2%80%93formaldehyde%20resins%3A%20molecular%20species%20distributions%20of%20methylolmelamines%20and%20some%20kinetics%20of%20methylolation&journal=J.%20Poly.%20Sci.%20Poly.%20Chem.%20Edi.&doi=10.1002%2Fpol.1977.170151005&volume=15&pages=2347-2365&publication_year=1977&author=Tomita%2CB"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="12"><p class="c-article-references__text" id="ref-CR12">Tomita, B. & Ono, H. Melamine–Formaldehyde resins: constitutional characterization by C-13 fourier transform NMR spectroscopy. <i>J. Poly. Sci. Poly. Chem. Edi.</i> <b>17</b>, 3205–3215 (1979).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1002/pol.1979.170171012" data-track-item_id="10.1002/pol.1979.170171012" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1002%2Fpol.1979.170171012" aria-label="Article reference 12" data-doi="10.1002/pol.1979.170171012">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaL3cXnt1Ol" aria-label="CAS reference 12">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 12" href="http://scholar.google.com/scholar_lookup?&title=Melamine%E2%80%93Formaldehyde%20resins%3A%20constitutional%20characterization%20by%20C-13%20fourier%20transform%20NMR%20spectroscopy&journal=J.%20Poly.%20Sci.%20Poly.%20Chem.%20Edi.&doi=10.1002%2Fpol.1979.170171012&volume=17&pages=3205-3215&publication_year=1979&author=Tomita%2CB&author=Ono%2CH"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="13"><p class="c-article-references__text" id="ref-CR13">Ebdon, J. R., Hunt, B. J., O’Rourke, W. T. S. & Parkin, J. Characterisation of some melamine-formaldehyde condensates and some cured resins by <sup>1</sup>H, <sup>13</sup>C and <sup>15</sup>N n.m.r. <i>Spectrosc. Br. Poly. J.</i> <b>20</b>, 327–334 (1988).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1002/pi.4980200405" data-track-item_id="10.1002/pi.4980200405" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1002%2Fpi.4980200405" aria-label="Article reference 13" data-doi="10.1002/pi.4980200405">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaL1cXlt12qtLg%3D" aria-label="CAS reference 13">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 13" href="http://scholar.google.com/scholar_lookup?&title=Characterisation%20of%20some%20melamine-formaldehyde%20condensates%20and%20some%20cured%20resins%20by%201H%2C%2013C%20and%2015N%20n.m.r&journal=Spectrosc.%20Br.%20Poly.%20J.&doi=10.1002%2Fpi.4980200405&volume=20&pages=327-334&publication_year=1988&author=Ebdon%2CJR&author=Hunt%2CBJ&author=O%E2%80%99Rourke%2CWTS&author=Parkin%2CJ"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="14"><p class="c-article-references__text" id="ref-CR14">Dawbarn, M., Ebdon, J. R. & Hewitt, S. J. Examination of some melamine formaldehyde adduct by C13 nuclear magnetic resonance. <i>Polymer</i> <b>19</b>, 1309–1312 (1978).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/0032-3861(78)90312-9" data-track-item_id="10.1016/0032-3861(78)90312-9" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2F0032-3861%2878%2990312-9" aria-label="Article reference 14" data-doi="10.1016/0032-3861(78)90312-9">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaE1MXksFOqs7c%3D" aria-label="CAS reference 14">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 14" href="http://scholar.google.com/scholar_lookup?&title=Examination%20of%20some%20melamine%20formaldehyde%20adduct%20by%20C13%20nuclear%20magnetic%20resonance&journal=Polymer&doi=10.1016%2F0032-3861%2878%2990312-9&volume=19&pages=1309-1312&publication_year=1978&author=Dawbarn%2CM&author=Ebdon%2CJR&author=Hewitt%2CSJ"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="15"><p class="c-article-references__text" id="ref-CR15">Sing, M. & Kumar, M. Preparation and characterisation of melamine-formaldehyde-polyvinylpyrrolidone polymer resin for better industrial uses over melamine resin. <i>J. Appl. Poly. Sci.</i> <b>114</b>, 1870–1878 (2009).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1002/app.30805" data-track-item_id="10.1002/app.30805" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1002%2Fapp.30805" aria-label="Article reference 15" data-doi="10.1002/app.30805">Article</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 15" href="http://scholar.google.com/scholar_lookup?&title=Preparation%20and%20characterisation%20of%20melamine-formaldehyde-polyvinylpyrrolidone%20polymer%20resin%20for%20better%20industrial%20uses%20over%20melamine%20resin&journal=J.%20Appl.%20Poly.%20Sci.&doi=10.1002%2Fapp.30805&volume=114&pages=1870-1878&publication_year=2009&author=Sing%2CM&author=Kumar%2CM"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="16"><p class="c-article-references__text" id="ref-CR16">Gordon, M., Halliwell, A. & Wilson, T. <i>The Chemistry of Polymerization Processes, SCI Monograph No. 20</i>, (Society of Chemical Industry, London, 1965).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 16" href="http://scholar.google.com/scholar_lookup?&title=The%20Chemistry%20of%20Polymerization%20Processes%2C%20SCI%20Monograph%20No.%2020&publication_year=1965&author=Gordon%2CM&author=Halliwell%2CA&author=Wilson%2CT"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="17"><p class="c-article-references__text" id="ref-CR17">Sato, K. & Naito, T. Studies on melamine resin: kinetics of acid-catalysed condensation of di and trimethylolmelamine. <i>Poly. J.</i> <b>5</b>, 144–157 (1973).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1295/polymj.5.144" data-track-item_id="10.1295/polymj.5.144" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1295%2Fpolymj.5.144" aria-label="Article reference 17" data-doi="10.1295/polymj.5.144">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaE2cXntFaisw%3D%3D" aria-label="CAS reference 17">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 17" href="http://scholar.google.com/scholar_lookup?&title=Studies%20on%20melamine%20resin%3A%20kinetics%20of%20acid-catalysed%20condensation%20of%20di%20and%20trimethylolmelamine&journal=Poly.%20J.&doi=10.1295%2Fpolymj.5.144&volume=5&pages=144-157&publication_year=1973&author=Sato%2CK&author=Naito%2CT"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="18"><p class="c-article-references__text" id="ref-CR18">Braun, D. & Legradic, V. Investigation of the melamine formadehyde reaction products. <i>Ange. Makro. Chemie.</i> <b>36</b>, 41–55 (1974).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1002/apmc.1974.050360104" data-track-item_id="10.1002/apmc.1974.050360104" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1002%2Fapmc.1974.050360104" aria-label="Article reference 18" data-doi="10.1002/apmc.1974.050360104">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaE2cXlt1Wmtr8%3D" aria-label="CAS reference 18">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 18" href="http://scholar.google.com/scholar_lookup?&title=Investigation%20of%20the%20melamine%20formadehyde%20reaction%20products&journal=Ange.%20Makro.%20Chemie.&doi=10.1002%2Fapmc.1974.050360104&volume=36&pages=41-55&publication_year=1974&author=Braun%2CD&author=Legradic%2CV"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="19"><p class="c-article-references__text" id="ref-CR19">Devallencourt, C., Saiter, J. M., Fafet, A. & Ubrich, E. Thermogravimetry/fourier transform infrared coupling investigations to study the thermal stability of melamine formaldehyde resin. <i>Thermo. Acta</i> <b>259</b>, 143–151 (1995).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/0040-6031(95)02262-Z" data-track-item_id="10.1016/0040-6031(95)02262-Z" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2F0040-6031%2895%2902262-Z" aria-label="Article reference 19" data-doi="10.1016/0040-6031(95)02262-Z">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaK2MXnvFWlt7k%3D" aria-label="CAS reference 19">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 19" href="http://scholar.google.com/scholar_lookup?&title=Thermogravimetry%2Ffourier%20transform%20infrared%20coupling%20investigations%20to%20study%20the%20thermal%20stability%20of%20melamine%20formaldehyde%20resin&journal=Thermo.%20Acta&doi=10.1016%2F0040-6031%2895%2902262-Z&volume=259&pages=143-151&publication_year=1995&author=Devallencourt%2CC&author=Saiter%2CJM&author=Fafet%2CA&author=Ubrich%2CE"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="20"><p class="c-article-references__text" id="ref-CR20">Manley, T. R. & Higgs, D. A. Thermal stability of melamine formaldehyde resins. <i>J. Poly. Sci. Symp.</i> <b>42</b>, 1377–1382 (1973).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1002/polc.5070420337" data-track-item_id="10.1002/polc.5070420337" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1002%2Fpolc.5070420337" aria-label="Article reference 20" data-doi="10.1002/polc.5070420337">Article</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 20" href="http://scholar.google.com/scholar_lookup?&title=Thermal%20stability%20of%20melamine%20formaldehyde%20resins&journal=J.%20Poly.%20Sci.%20Symp.&doi=10.1002%2Fpolc.5070420337&volume=42&pages=1377-1382&publication_year=1973&author=Manley%2CTR&author=Higgs%2CDA"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="21"><p class="c-article-references__text" id="ref-CR21">Moore, W. R. & Donnelly, E. Thermal degradation of melamine formaldehyde resins. <i>J. Appl. Chem.</i> <b>13</b>, 537–543 (1963).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1002/jctb.5010131202" data-track-item_id="10.1002/jctb.5010131202" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1002%2Fjctb.5010131202" aria-label="Article reference 21" data-doi="10.1002/jctb.5010131202">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaF2cXjtFKquw%3D%3D" aria-label="CAS reference 21">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 21" href="http://scholar.google.com/scholar_lookup?&title=Thermal%20degradation%20of%20melamine%20formaldehyde%20resins&journal=J.%20Appl.%20Chem.&doi=10.1002%2Fjctb.5010131202&volume=13&pages=537-543&publication_year=1963&author=Moore%2CWR&author=Donnelly%2CE"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="22"><p class="c-article-references__text" id="ref-CR22">Youliang, H., Lin, Y. & Xiaowen, Z. Synthesis of the melamine–formaldehyde polycondensate and its thermal stabilization effect on polyoxymethylene. <i>Polymer</i> <b>47</b>, 2649–2659 (2006).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/j.polymer.2006.02.050" data-track-item_id="10.1016/j.polymer.2006.02.050" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2Fj.polymer.2006.02.050" aria-label="Article reference 22" data-doi="10.1016/j.polymer.2006.02.050">Article</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 22" href="http://scholar.google.com/scholar_lookup?&title=Synthesis%20of%20the%20melamine%E2%80%93formaldehyde%20polycondensate%20and%20its%20thermal%20stabilization%20effect%20on%20polyoxymethylene&journal=Polymer&doi=10.1016%2Fj.polymer.2006.02.050&volume=47&pages=2649-2659&publication_year=2006&author=Youliang%2CH&author=Lin%2CY&author=Xiaowen%2CZ"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="23"><p class="c-article-references__text" id="ref-CR23">Vo, D. T., Himmelsbach, M., Haunschmidt, M., Buchberger, W., Schwarzinger, C. & Klambfl, C. W. Improved analysis of melamine-formaldehyde resins by capillary zone electrophoresis-mass spectrometry using ion-trap and quadrupole-time-of-flight mass spectrometers. <i>J. Chromat. A</i> <b>1213</b>, 83–87 (2008).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/j.chroma.2008.07.002" data-track-item_id="10.1016/j.chroma.2008.07.002" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2Fj.chroma.2008.07.002" aria-label="Article reference 23" data-doi="10.1016/j.chroma.2008.07.002">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BD1cXhsVajt7fF" aria-label="CAS reference 23">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 23" href="http://scholar.google.com/scholar_lookup?&title=Improved%20analysis%20of%20melamine-formaldehyde%20resins%20by%20capillary%20zone%20electrophoresis-mass%20spectrometry%20using%20ion-trap%20and%20quadrupole-time-of-flight%20mass%20spectrometers&journal=J.%20Chromat.%20A&doi=10.1016%2Fj.chroma.2008.07.002&volume=1213&pages=83-87&publication_year=2008&author=Vo%2CDT&author=Himmelsbach%2CM&author=Haunschmidt%2CM&author=Buchberger%2CW&author=Schwarzinger%2CC&author=Klambfl%2CCW"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="24"><p class="c-article-references__text" id="ref-CR24">Berge, A. & Mejdell, T. Melamine formaldehyde compounds. The active species in acid catalyzed reactions. <i>Polymer</i> <b>47</b>, 3249–3256 (2006).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/j.polymer.2006.02.054" data-track-item_id="10.1016/j.polymer.2006.02.054" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2Fj.polymer.2006.02.054" aria-label="Article reference 24" data-doi="10.1016/j.polymer.2006.02.054">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BD28XksFaku7o%3D" aria-label="CAS reference 24">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 24" href="http://scholar.google.com/scholar_lookup?&title=Melamine%20formaldehyde%20compounds.%20The%20active%20species%20in%20acid%20catalyzed%20reactions&journal=Polymer&doi=10.1016%2Fj.polymer.2006.02.054&volume=47&pages=3249-3256&publication_year=2006&author=Berge%2CA&author=Mejdell%2CT"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="25"><p class="c-article-references__text" id="ref-CR25">Naske, R., Dietrich, K., Reinisch, G. & Refler, G. The initial stage of the reaction of melamine with formaldehyde. <i>J. Macromol. Sci. Chem. A</i> <b>23</b>, 579–596 (1986).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1080/00222338608058497" data-track-item_id="10.1080/00222338608058497" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1080%2F00222338608058497" aria-label="Article reference 25" data-doi="10.1080/00222338608058497">Article</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 25" href="http://scholar.google.com/scholar_lookup?&title=The%20initial%20stage%20of%20the%20reaction%20of%20melamine%20with%20formaldehyde&journal=J.%20Macromol.%20Sci.%20Chem.%20A&doi=10.1080%2F00222338608058497&volume=23&pages=579-596&publication_year=1986&author=Naske%2CR&author=Dietrich%2CK&author=Reinisch%2CG&author=Refler%2CG"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="26"><p class="c-article-references__text" id="ref-CR26">Bauer, D. R. & Dickie, R. A. Crosslinking chemistry and network structure in organic coatings. I. Cure of melamine formaldehyde/acrylic copolymer films. <i>J. Poly. Sci. Poly. Phys. Ed.</i> <b>18</b>, 1997–2014 (1980).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1002/pol.1980.180181001" data-track-item_id="10.1002/pol.1980.180181001" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1002%2Fpol.1980.180181001" aria-label="Article reference 26" data-doi="10.1002/pol.1980.180181001">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaL3cXmt1Wqtbg%3D" aria-label="CAS reference 26">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 26" href="http://scholar.google.com/scholar_lookup?&title=Crosslinking%20chemistry%20and%20network%20structure%20in%20organic%20coatings.%20I.%20Cure%20of%20melamine%20formaldehyde%2Facrylic%20copolymer%20films&journal=J.%20Poly.%20Sci.%20Poly.%20Phys.%20Ed.&doi=10.1002%2Fpol.1980.180181001&volume=18&pages=1997-2014&publication_year=1980&author=Bauer%2CDR&author=Dickie%2CRA"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="27"><p class="c-article-references__text" id="ref-CR27">David, B. R. Melamine/formaldehyde crosslinkers: characterization, network formation and crosslink degradation. <i>Prog. Org. Coat.</i> <b>14</b>, 193–218 (1986).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/0033-0655(86)80001-2" data-track-item_id="10.1016/0033-0655(86)80001-2" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2F0033-0655%2886%2980001-2" aria-label="Article reference 27" data-doi="10.1016/0033-0655(86)80001-2">Article</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 27" href="http://scholar.google.com/scholar_lookup?&title=Melamine%2Fformaldehyde%20crosslinkers%3A%20characterization%2C%20network%20formation%20and%20crosslink%20degradation&journal=Prog.%20Org.%20Coat.&doi=10.1016%2F0033-0655%2886%2980001-2&volume=14&pages=193-218&publication_year=1986&author=David%2CBR"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="28"><p class="c-article-references__text" id="ref-CR28">Wilson, R. C. & Pfohl, W. F. Study of cross-linking reactions of melamine/formaldehyde resin with hydroxyl functional polyester by generalized 2-D infrared spectroscopy. <i>Vibrat. Spect.</i> <b>23</b>, 13–22 (2000).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/S0924-2031(99)00072-7" data-track-item_id="10.1016/S0924-2031(99)00072-7" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2FS0924-2031%2899%2900072-7" aria-label="Article reference 28" data-doi="10.1016/S0924-2031(99)00072-7">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BD3cXhvVOrs7k%3D" aria-label="CAS reference 28">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 28" href="http://scholar.google.com/scholar_lookup?&title=Study%20of%20cross-linking%20reactions%20of%20melamine%2Fformaldehyde%20resin%20with%20hydroxyl%20functional%20polyester%20by%20generalized%202-D%20infrared%20spectroscopy&journal=Vibrat.%20Spect.&doi=10.1016%2FS0924-2031%2899%2900072-7&volume=23&pages=13-22&publication_year=2000&author=Wilson%2CRC&author=Pfohl%2CWF"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="29"><p class="c-article-references__text" id="ref-CR29">Scheepers, M. L., Gelan, J. M., Carleer, R. A., Adriaensens, P. J. & Vanderzande, D. J. Investigation of melamine-formaldehyde cure by fourier transform Raman spectroscopy. <i>Vibrat. Spect.</i> <b>6</b>, 55–69 (1993).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/0924-2031(93)87022-L" data-track-item_id="10.1016/0924-2031(93)87022-L" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2F0924-2031%2893%2987022-L" aria-label="Article reference 29" data-doi="10.1016/0924-2031(93)87022-L">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaK3sXmsFWgsrk%3D" aria-label="CAS reference 29">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 29" href="http://scholar.google.com/scholar_lookup?&title=Investigation%20of%20melamine-formaldehyde%20cure%20by%20fourier%20transform%20Raman%20spectroscopy&journal=Vibrat.%20Spect.&doi=10.1016%2F0924-2031%2893%2987022-L&volume=6&pages=55-69&publication_year=1993&author=Scheepers%2CML&author=Gelan%2CJM&author=Carleer%2CRA&author=Adriaensens%2CPJ&author=Vanderzande%2CDJ"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="30"><p class="c-article-references__text" id="ref-CR30">Mequanint, K. & Sanderson, R. Nano-structure phosphorus-containing polyurethane dispersions: synthesis and crosslinking with melamine formaldehyde resin. <i>Polymer</i> <b>44</b>, 2631–2639 (2003).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/S0032-3861(03)00154-X" data-track-item_id="10.1016/S0032-3861(03)00154-X" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2FS0032-3861%2803%2900154-X" aria-label="Article reference 30" data-doi="10.1016/S0032-3861(03)00154-X">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BD3sXis1aqtb0%3D" aria-label="CAS reference 30">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 30" href="http://scholar.google.com/scholar_lookup?&title=Nano-structure%20phosphorus-containing%20polyurethane%20dispersions%3A%20synthesis%20and%20crosslinking%20with%20melamine%20formaldehyde%20resin&journal=Polymer&doi=10.1016%2FS0032-3861%2803%2900154-X&volume=44&pages=2631-2639&publication_year=2003&author=Mequanint%2CK&author=Sanderson%2CR"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="31"><p class="c-article-references__text" id="ref-CR31">Manfred, R., Hartmut, B., Sergey, I., Valery, P., Paul, L. & Primachenko, O. N. The reaction mechanism of the transetherification and crosslinking of melamine resins. <i>Macromol. Symp.</i> <b>217</b>, 431–443 (2004).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1002/masy.200451339" data-track-item_id="10.1002/masy.200451339" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1002%2Fmasy.200451339" aria-label="Article reference 31" data-doi="10.1002/masy.200451339">Article</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 31" href="http://scholar.google.com/scholar_lookup?&title=The%20reaction%20mechanism%20of%20the%20transetherification%20and%20crosslinking%20of%20melamine%20resins&journal=Macromol.%20Symp.&doi=10.1002%2Fmasy.200451339&volume=217&pages=431-443&publication_year=2004&author=Manfred%2CR&author=Hartmut%2CB&author=Sergey%2CI&author=Valery%2CP&author=Paul%2CL&author=Primachenko%2CON"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="32"><p class="c-article-references__text" id="ref-CR32">Blank, W. J. Reaction mechanism of amino resin. <i>J. Coat. Techn.</i> <b>51</b>, 61–70 (1979).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaE1MXlslKksr0%3D" aria-label="CAS reference 32">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 32" href="http://scholar.google.com/scholar_lookup?&title=Reaction%20mechanism%20of%20amino%20resin&journal=J.%20Coat.%20Techn.&volume=51&pages=61-70&publication_year=1979&author=Blank%2CWJ"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="33"><p class="c-article-references__text" id="ref-CR33">Anderson, I. H., Cawley, M. & Steedman, W. Melamine-formaldehyde resins: an examination of some model compound systems. <i>Br. Polym. J.</i> <b>1</b>, 24–28 (1969).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1002/pi.4980010104" data-track-item_id="10.1002/pi.4980010104" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1002%2Fpi.4980010104" aria-label="Article reference 33" data-doi="10.1002/pi.4980010104">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaF1MXktVegtLw%3D" aria-label="CAS reference 33">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 33" href="http://scholar.google.com/scholar_lookup?&title=Melamine-formaldehyde%20resins%3A%20an%20examination%20of%20some%20model%20compound%20systems&journal=Br.%20Polym.%20J.&doi=10.1002%2Fpi.4980010104&volume=1&pages=24-28&publication_year=1969&author=Anderson%2CIH&author=Cawley%2CM&author=Steedman%2CW"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="34"><p class="c-article-references__text" id="ref-CR34">Dawbarn, M., Ebdon, J. R. & Hewitt, S. J. Examination of some melamine formaldehyde adduct by C13 nuclear magnetic resonance. <i>Polymer</i> <b>19</b>, 1309–1312 (1978).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/0032-3861(78)90312-9" data-track-item_id="10.1016/0032-3861(78)90312-9" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2F0032-3861%2878%2990312-9" aria-label="Article reference 34" data-doi="10.1016/0032-3861(78)90312-9">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaE1MXksFOqs7c%3D" aria-label="CAS reference 34">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 34" href="http://scholar.google.com/scholar_lookup?&title=Examination%20of%20some%20melamine%20formaldehyde%20adduct%20by%20C13%20nuclear%20magnetic%20resonance&journal=Polymer&doi=10.1016%2F0032-3861%2878%2990312-9&volume=19&pages=1309-1312&publication_year=1978&author=Dawbarn%2CM&author=Ebdon%2CJR&author=Hewitt%2CSJ"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="35"><p class="c-article-references__text" id="ref-CR35">Pizzi, A. <i>Handbook of Adhesive Technology</i> 2nd edn (eds Pizzi and Mittal) Ch. 32 653–680 (Marcel Dekker, France, Inc., 2003).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 35" href="http://scholar.google.com/scholar_lookup?&title=Handbook%20of%20Adhesive%20Technology&pages=653-680&publication_year=2003&author=Pizzi%2CA"> Google Scholar</a> </p></li></ol><p class="c-article-references__download u-hide-print"><a data-track="click" data-track-action="download citation references" data-track-label="link" rel="nofollow" href="https://citation-needed.springer.com/v2/references/10.1038/pj.2012.162?format=refman&flavour=references">Download references<svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-download-medium"></use></svg></a></p></div></div></div></section></div><section aria-labelledby="author-information" data-title="Author information"><div class="c-article-section" id="author-information-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="author-information">Author information</h2><div class="c-article-section__content" id="author-information-content"><h3 class="c-article__sub-heading" id="affiliations">Authors and Affiliations</h3><ol class="c-article-author-affiliation__list"><li id="Aff1"><p class="c-article-author-affiliation__address">Department of Chemical Engineering, The Petroleum Institute, Abu Dhabi, UAE</p><p class="c-article-author-affiliation__authors-list">Dyana J Merline, Sulafudin Vukusic & Ahmed A Abdala</p></li></ol><div class="u-js-hide u-hide-print" data-test="author-info"><span class="c-article__sub-heading">Authors</span><ol class="c-article-authors-search u-list-reset"><li id="auth-Dyana_J-Merline-Aff1"><span class="c-article-authors-search__title u-h3 js-search-name">Dyana J Merline</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Dyana%20J%20Merline" class="c-article-button" data-track="click" data-track-action="author link - 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Melamine formaldehyde: curing studies and reaction mechanism. <i>Polym J</i> <b>45</b>, 413–419 (2013). https://doi.org/10.1038/pj.2012.162</p><p class="c-bibliographic-information__download-citation u-hide-print"><a data-test="citation-link" data-track="click" data-track-action="download article citation" data-track-label="link" data-track-external="" rel="nofollow" href="https://citation-needed.springer.com/v2/references/10.1038/pj.2012.162?format=refman&flavour=citation">Download citation<svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-download-medium"></use></svg></a></p><ul class="c-bibliographic-information__list" data-test="publication-history"><li class="c-bibliographic-information__list-item"><p>Received<span class="u-hide">: </span><span class="c-bibliographic-information__value"><time datetime="2012-04-08">08 April 2012</time></span></p></li><li class="c-bibliographic-information__list-item"><p>Revised<span class="u-hide">: </span><span class="c-bibliographic-information__value"><time datetime="2012-07-09">09 July 2012</time></span></p></li><li class="c-bibliographic-information__list-item"><p>Accepted<span class="u-hide">: </span><span class="c-bibliographic-information__value"><time datetime="2012-07-12">12 July 2012</time></span></p></li><li class="c-bibliographic-information__list-item"><p>Published<span class="u-hide">: </span><span class="c-bibliographic-information__value"><time datetime="2012-10-17">17 October 2012</time></span></p></li><li class="c-bibliographic-information__list-item"><p>Issue Date<span class="u-hide">: </span><span class="c-bibliographic-information__value"><time datetime="2013-04">April 2013</time></span></p></li><li class="c-bibliographic-information__list-item c-bibliographic-information__list-item--full-width"><p><abbr title="Digital Object Identifier">DOI</abbr><span class="u-hide">: 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formaldehyde</a></span></li><li class="c-article-subject-list__subject"><span><a href="/search?query=thermal%20properties&facet-discipline="Chemistry"" data-track="click" data-track-action="view keyword" data-track-label="link">thermal properties</a></span></li><li class="c-article-subject-list__subject"><span><a href="/search?query=thermosetting%20resin&facet-discipline="Chemistry"" data-track="click" data-track-action="view keyword" data-track-label="link">thermosetting resin</a></span></li></ul><div data-component="article-info-list"></div></div></div></div></div></section> </div> <section> <div class="c-article-section js-article-section" id="further-reading-section" data-test="further-reading-section"> <h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="further-reading">This article is cited by</h2> <div class="c-article-section__content js-collapsible-section" id="further-reading-content"> <ul class="c-article-further-reading__list" 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