木质素胺改性豆粕基胶黏剂的制备及性能

采用曼尼希反应,将玉米芯木质素改性制备木质素胺(AL),然后与水性聚酰胺(PAE)、聚乙二醇二缩水甘油醚(PEGDE)混合,以豆粕粉为原料,通过AL/PAE/PEGDE改性制备高固体含量的豆粕基胶黏剂(豆胶)。对豆胶性能进行表征和测试,结果表明:复合改性豆胶固化后的红外谱图中酰胺Ⅰ带吸收峰由1632 cm^(-1)处蓝移至1640 cm^(-1),酰胺Ⅱ带吸收峰由1533 cm^(-1)蓝移至1538 cm^(-1),此现象说明固化豆胶中形成了结构致密相互交联的网状结构;热重分析结果也说明PAE、PEGDE、AL与蛋白质分子之间形成了结构更为致密的网络结构;流变行为分析显示固化豆胶具有假塑性流体的特征;改性豆胶含固体高达42.5%,而表观黏度仅为3746 mPa·s,具有较好的涂布性能,适于工业化应用;所得胶合板的胶合强度为0.86 MPa,合格率100%,符合国家Ⅱ类胶合板的标准要求(胶合强度≥0.70 MPa,合格率≥90%)。

Preparation and Properties of Soybean Meal Adhesives Modified by Lignin Amine

Lignin amine(AL) was prepared by modifying corn cob via Mannich reaction, and then AL was mixed with water-based polyamide(PAE) and polyethylene glycol diglycidyl ether(PEGDE). Soybean meal was used as raw material to prepare soybean gum with high solid content by AL/PAE/PEGDE modification. The properties of soybean gum were characterized and tested, and the FT-IR results showed that the absorption peak of amide Ⅰ of the soybean meal adhesive modified with AL, PAE, and PEGDE after curing shifted from 1632 cm^-1 to 1640 cm^-1, and amide Ⅱ shifted from 1533 cm^-1 to 1538 cm^-1. And the shift suggested that the cured adhesive possessed a dense and cross-linking structure. The TGA results also showed that the network structure between PAE, PEGDE, AL, and protein molecules was more compact, and the rheological behavior analysis showed that the cured soybean meal adhesive had the characteristics of pseudoplastic fluid. The solid content in the modified adhesive was as high as 42.5%, while the apparent viscosity was simply 3 746 mPa·s, which was suitable for application in plywood industry. The wet bonding strength of the prepared plywood reached 0.86 MPa and the pass rate was 100%, which meet the national standard for type II plywood(bonding strength≥0.70 MPa, and the pass rate≥90%).