无醛玉米秸秆木质素基木材胶黏剂的制备与性能

Preparation and Properties of Corn Stalk Lignin Formaldehyde-free Wood Adhesives

将玉米秸秆木质素进行羟乙基化改性,添加一定量环氧氯丙烷制备了无醛人造板用木材胶黏剂。利用胶接强度测试以及红外光谱分析和热重分析对胶黏剂的性能进行了表征。结果表明,随着环氧氯丙烷添加量的增大,胶合板的剪切强度呈现先增大后降低的趋势,添加量为30份时,剪切强度最大(干胶合强度1.58MPa),达到国家II类胶合板标准,此时胶黏剂固化样品的热稳定性最好。木质素基胶黏剂中添加一定量聚丙烯酸酯乳液可以明显提升胶黏剂的粘接性能和耐水性能,其干胶合强度最高可达2.73MPa,湿胶合强度最高可达1.09MPa。聚丙烯酸酯乳液的加入对胶黏剂在400℃以内的耐热性没有明显影响。

A kind of formaldehyde-free wood adhesive was prepared by blending glyoxalated corn stalk lignin with the curing agent epichlorohydrin. The properties of the adhesives were characterized by the test of bonding strength, infrared spectrum analysis and thermogravimetric analysis. The results showed that with the increase of amount of epiehlorohydrin, the shear strength of the plywood firstly increased and then deereased. When the adding amount of epichlorohydrin was 30 parts per 100 parts of modified lignin, the shear strength of the plywood was the largest （1.58MPa for dry bonding strength） and could reach the standard of type II plywood. At this time, the thermal stability of the cured sample was the best. The adhe- sion properties and water resistance of the wood adhesive could be improved by mixing with certain amount of polyacrylate emulsion. The dry adhesive strength of the adhesive eould be up to 2.73MPa and the wet adhesive strength could be up to 1.09MPa after adding the emulsion. The addition of polyacrylate emulsion had no significant effect on the heat resistance of adhesive below 400℃.