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以玉米淀粉、聚乙烯醇(PVA)为主要原料,采用酸碱处理法制备了淀粉胶粘剂;然后用异氰酸酯进行改性,制备了木材用复合淀粉胶粘剂。研究结果表明:碱处理能影响淀粉间的氢键强度,酸处理时间相同时,随着碱处理时间的延长,淀粉的羟基峰均向长波数方向移动,羟基移动波数和复合淀粉胶粘剂的胶接强度均呈先升后降态势,碱处理40 min后复合淀粉胶粘剂的胶接强度(1.345 MPa)相对最大;淀粉胶粘剂的结晶度和耐热性随碱处理时间延长呈先降后升态势,碱处理40 min时淀粉的结晶度降低了10.6%,初始热降解温度降低了15%;碱处理能腐蚀淀粉颗粒表面,碱处理20 min时淀粉颗粒的被腐蚀程度相对最低,而PVA与淀粉的包覆效果在碱处理40min时相对最佳。
Using corn starch and polyvinyl alcohol (PVA) as main raw materials, the starch adhesive was prepared by acid-base treatment and then modified with isocyanate to prepare the composite starch adhesive for wood. The results showed that alkali treatment could affect the hydrogen bonding strength between starch and acid treatment time. With the prolonging of alkali treatment time, the hydroxyl peak of starch all moved in the direction of longer wave number. The strength of the starch adhesive firstly and then decreased. The adhesive strength (1.345 MPa) of the composite starch adhesive was the maximum after 40 min of alkali treatment. The crystallinity and heat resistance of the starch adhesive decreased first and then increased with alkali treatment time. The crystallinity of starch decreased by 10.6% and the initial thermal degradation temperature decreased by 15% after 40 min treatment. Alkali treatment could erode the surface of starch granules, while the alkali granules had the lowest corrosion degree at 20 min. Cover effect is relatively the best in the alkali treatment 40min.