脲醛树脂中引入电解质作用的研究

The Investigation of the Effect of Electrolyte on Urea-Formaldehyde Resin

采用FTIR、DSC等分析手段对一种可以有效降低生产成本的脲醛树脂活性剂进行研究。结果表明:活性剂的主要成分是羟甲基脲,电解质没有与脲醛衍生物产生化学结合,活性剂降低了树脂表面张力,增大了对木材的润湿性,在参与固化反应的过程中,活性剂降低了脲醛树脂固化反应的活化能,说明有更多的树脂分子参与到固化反应中来,宏观上表现出提高了脲醛树脂的粘接效率;设计了一种脲醛树脂合成工艺,在合成过程中合理引入电解质,通过压制胶合板、纸板等试验,对产物的性能进行了综合评价,结论认为由于电解质的引入,加快了反应速度,提高了粘接强度,但也导致了胶接制品的湿强度下降;从理论上对电解质发生的作用机制进行探索,为有效控制脲醛树脂的合成和应用成本提供一种可操作的方法。

A kind of active reagent that could reduce the cost of urea-formaldehyde （UF） manufacture successfully was investigated by FTIR and DSC analysis. The results indicated that the main efficient component of active reagent was the methylolated urea, and the electrolyte had no chemical linking with urea derivatives. The active reagent reduced the surface tension of resin which improves the resin wettability onto wood. During the solidifying reaction, active reagent would reduce the activated energy of UF resin which implied that more resin molecules had attended the reaction and the bonding efficiency was improved macroscopically. The plywood and paperboard testing indicated that the synthetic technology introduced electrolyte properly could improve reaction rate and bonding strength, but reduced the tensile strengthen under the wet condition. The effect of electrolyte was discussed theoretically. It offered a good method for controlling the UF synthesis and cost during application.