Journal of Adhesion and Interface (접착 및 계면)

The Society of Adhesion and Interface, Korea (한국접착및계면학회)
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Curing Characteristics of Low Molar Ratio Urea-Formaldehyde Resins

  • Fan, Dongbin (School of Material Science & Technology, Beijing Forestry University) ;
  • Li, Jianzhang (School of Material Science & Technology, Beijing Forestry University) ;
  • Mao, An (School of Material Science & Technology, Beijing Forestry University)
  • Received : 2006.11.02
  • Accepted : 2006.11.21
  • Published : 2006.12.30
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Abstract

Five low molar ratio urea-formaldehyde (LUF) resins were synthesized in this study. The effects of molar ratio, free formaldehyde content, and catalysts on the curing characteristics of LUF resins were studied by measuring its free formaldehyde content, pH value change after catalysts added, curing rate, and pot life, observing its cured appearance, and analyzing its thermal behavior. The results indicate that: 1) The LUF resin with lower molar ratio than 1.0 can still cure; 2) Free formaldehyde content is not the main factor in affecting curing rate of LUF resin; 3) Compared with ammonium chloride as a traditional catalyst, persulfate salts markedly accelerate the curing rate of LUF resin, and result in the different appearance; 4) the addition of sodium chloride to catalysts can accelerate the curing rate of LUF resin, but the effect is moderate.

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