冷榨核桃饼基木材胶黏剂的制备及性能研究

Preparation and performance of cold-pressed walnut cake based wood adhesive

为了提升蛋白基胶黏剂的耐水性,以支化聚合物(PEI)为改性剂,以160目核桃饼粉为原料,在碱性条件下进行热解处理后,考察不同反应条件及PEI添加量对胶合板胶接强度的影响。并利用差示扫描量热仪(DSC)对不同PEI添加量下胶黏剂的固化特征进行了测试,借助FT-IR分析对固化前后基团的变化进行了表征。结果表明,PEI添加量30%~40%、预处理温度90℃、预处理时间1 h条件下制备的胶黏剂可满足Ⅲ类胶合板的使用标准。总体而言PEI添加量越多,胶黏剂体系的固化峰值温度越高,说明体系中物质间的化学反应程度越高,越有利于胶接强度的提升。在胶黏剂固化过程中,PEI中的活性氨基和亚氨基与核桃饼热解液蛋白质分子中的羧基和氨基之间发生了化学键合,有助于体系胶接强度的提升和耐水性的改善。因此,PEI的使用可有效提升核桃饼基木材胶黏剂的耐水性和胶接强度。

In order to improve the water resistance of protein based wood adhesive, the branched polymers(PEI) was used as modifier, walnut cake with 160 meshes was employed as raw material, the effects of reaction conditions and PEI dosage on bond strength of plywood were investigated by heating under alkaline conditions. Meanwhile, the curing characteristic of adhesive with different PEI dosage was analyzed by DSC, and the functional groups before and after curing were investigated by FT-IR.The results indicated that the adhesive prepared under the conditions of PEI dosage 30%-40%, pretreatment temperature 90℃ and pretreatment time 1 h could meet plywood standard of III type.Overall, the more the PEI dosage was added, the higher the curing peak temperature was, which meant the higher the degree of chemical reaction, the better the improvement of the bond strength. FT-IR results showed that chemical bonding between active amino and imino groups in PEI and carboxyl and amino groups in protein of walnut cake pyrolytic solution existed during curing process.Therefore, PEI was helpful for improvement of water resistance and bond strength of walnut cake based wood adhesive.