摘要
本文用FTIR分析比较了脲醛树脂合成过程中主要基团含量的变化情况,探讨了脲醛树脂胶粘剂合成机理。分析研究表明:随着缩聚反应的进行,醛基吸收峰呈明显减弱;降低反应介质的pH后,羟基含量减少明显,此阶段是整个脲醛树脂合成的关键阶段;后续加入尿素调整F∶U,游离甲醛与尿素的反应比较缓慢,醛基吸收峰面积减少幅度不大;在接近脲醛树脂缩合反应终点时有甲醚键副反应物产生。
The contents of main radicals in the different stages of UF resin synthesis were compared by ZFIR Spectra in this article and its synthetic mechanism was discussed. The results showed that with polycondensation reaction going, the absorption peaks of - aldehyde turned weak obviously. The content of hydroxy dropped fast after the decrease of pH value. The stage of polycondensation was a key period in the whole resin preparation. Later, when urea was added to decrease the ratio of F： U, the reaction of free formaldehyde and urea was slower in comparison with the polycondensation process, and the reduction of the area of absorption peaks was not noticeable. Approaching to the finishing point of urea formaldehyde resin polycondensation process, methyl ether was produced as a by-product.
出处
《四川林业科技》
2007年第1期77-80,共4页
Journal of Sichuan Forestry Science and Technology
