单宁改性室温固化型MUF树脂性能研究

以3种单宁为改性剂，研究了不同种单宁、不同添加阶段、不同添加量对三聚氰胺-尿素-甲醛 （MUF） 共缩聚树脂性能的影响，并优选结果进行红外 （FT IR）、核磁碳谱 (13C NMR) 测试分析。结果表明：在 “碱-酸-碱” 工艺过程中，在一碱阶段添加7%的杨梅单宁改性三聚氰胺-尿素-甲醛树脂效果较好，所制备树脂粘度适宜、游离甲醛含量低，所制胶合木干、湿状剪切强度均满足国家结构集成材用胶标准。结构分析表明，单宁的引入会在一定层度上阻碍加成反应与缩聚反应的进行，经单宁改性后树脂体系中C O C伸缩振动增强，C N伸缩振动减弱，与核磁碳谱测试结果中MUF Y醚键增加、桥键减少的结果相吻合。

The Performances of MUF Resin Modified by TanninsCuring at Room Temperature

In this paper, three kinds of tannins were used as modifiers. The influences of tannin variety, adding stages and adding amount on the performance of MUF resin were studied, and the optimal results were analyzed with the test methods of FT IR and 13C NMR. The results showed that add 7% bayberry tannin to modify the MUF resin during the first alkali stage had the best results. The resin has an appropriate viscosity and low free formaldehyde content. The performances of glulam that made by the modified MUF resin satisfied the standardm on integrated structural timber in China. The results of FT IR showed that adding tannin would impede the reaction of additive reaction and polycondensation, enhance the stretching vibration of C O C key in the modified resin, and weaken the stretching vibration of C N key. It agreed with the result of 13C NMR that the ether bond increased and the bridge bond decreased.