摘要
用13 CNMR研究脲醛树脂缩聚反应阶段结构形成特征 ,结果表明 :在传统合成工艺条件下 ,与树脂化反应平行地存在一个较强烈的水解反应 ;二次缩聚有利于降低树脂中二亚甲基醚键的含量 ,并可提高树脂交联程度 ;高温缩聚所得的树脂结构简单并有利于降低醚键的含量和提高树脂贮存稳定性 ;降低缩聚阶段的pH值有利于提高树脂交联程度 ,降低游离甲醛的含量。
The structure feature of urea formaldehyde(UF) resin at condensation reaction stage was investigated with high resolution 13 C-NMR (DRX-500).The result shows that,under traditional process conditions, 1) a fierce hydrolysis reaction occurs at the same time of the methylene bond formation step; 2) the secondary urea addition reaction is favorable to decreasing the contents of dimethylene ether linkage and incresing the cross linkage; 3) methylene bond produced at high temperature with relatively simple structure is also favorable to decreasing the contents of dimethylene ether linkages and enhencing the stability of final product; 4) a less value of pH at condensation stage is favorable to decreaing the contents of free formaldehyde and increasing the crosslinking extent as well.
出处
《粘接》
CAS
2000年第1期12-16,共5页
Adhesion
基金
云南省应用基础研究基金!资助项目编号 97C0 2 1Q
关键词
脲醛树脂
缩聚
结构
UF resin Condensation Structure 13 C-NMR
