Starch adhesive was synthesized with com starch oxidized by sodium hypochlorite sodium, and then starch-isocyanate composite adhesive was prepared by blending modification with functional inner-crosslinking agent ( isocyanate). The effects of pH, polyvinyl alcohol (PVA) concentration, PVA dosage, starch content, and mixing ratio of isocyanate on the bonding properties of the starch adhesive were studied under different experimental conditions. The best bonding strength and water resistance were obtained as PVA concentration 10% , ratio of starch to PVA 3:5, ratio of starch to water 3 '· 8, and using oxidized modified starch. XPS analysis shows that chemical bond formation between isocyanate and hydroxyl of starch adhesive and wood is key to improving bonding strength and water resistance. The modified starch adhesive exhibits better adhesive properties, which meet the application requirements for type II plywood.%采用次氯酸钠对玉米淀粉进行氧化制备淀粉胶黏剂,再用功能内交联剂(异氰酸酯)共混改性制备淀粉基复合胶黏剂.考查了复合胶黏剂体系的pH、PVA质量分数与用量、淀粉用量、异氰酸酯加入比例对淀粉基复合胶黏剂胶接性能的影响.胶接实验结果表明:利用变性的氧化淀粉,PVA质量分数为10％,PVA加入比例为3/5,淀粉与水比为3/8时,获得最佳的胶结强度和耐水性能.采用XPS分析胶层化学结构,结果表明:异氰酸酯与淀粉胶黏剂、木材中的羟基反应形成化学键结合是提高胶接强度和耐水性关键所在.所制得的改性淀粉胶黏剂性能更加优异,符合Ⅱ类胶合板的使用要求.
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