PMUF共缩聚树脂制备过程中分子结构变化特征的研究

Structure change of a PMUF co-condensed resin during its preparation.

该文采用^(13)C核磁共振(^(13)C-NMR)分析方法,对典型工艺合成条件下制备的苯酚-三聚氰胺-尿素-甲醛树脂(PMUF)进行结构分析,判断在树脂制备过程中树脂的分子结构变化特征,为寻找PMUF树脂的较佳合成工艺条件提供理论依据.结果发现向脲醛树脂(UF)中加入三聚氰胺后,谱图简化,认为三聚氰胺与尿素之间可能通过亚甲基醚键连接.几乎所有的苯酚在树脂中也都处于游离状态,它既未与UF树脂或三聚氰胺树脂(MF)发生反应,也未与游离甲醛发生反应,因此,在树脂合成后期向树脂中加入苯酚的方法不能保证共缩聚反应的发生.

To lay a theoretical foundation for the determination of a better synthesizing condition, the structure of phenol-melamine-urea-formaldehyde resin （PMUF） synthesized in a typical way and the structure changes during its preparation were examined by ^13C nuclear magnetic resonance（^13C-NMR） spectroscopy in this paper. The results showed that the NMR graph became simpler after adding melamine to UF resin. So the formation of methyl ether bridges between melamine and urea was possible. Almost all of the phenol was free in this resin, ie phenol didn＇t co-condense with UF species, MF species, or even formaldehyde. So the method to add phenol to MUF resin in the end of the preparation of MUF resin couldn＇ t guarantee the co-condensation between MUF resin and phenol to come forth.