ABSTRACT

Soybean meal-based adhesives (SMAs) commercially applied in wood-based composites require stable bonding properties. However, the structure and properties of SMAs are not as stable as synthetic resins, which significantly affect their performances. In this study, the structure–property evolution of a SMA with working time was systematically investigated. The findings revealed that the secondary structure, microstructure, crosslinking density, zeta potential, nitrogen solubility index, viscosity, wood permeability, and bonding properties of SMA considerably vary with working time. The changes in adhesive properties were correlated with the dissolution of SM particles in crosslinker solution and the increased pre-curing of liquid SMA with working time resulting from the crosslinking reactions between the dissolved SM and the crosslinker. Preferably, SMA at the working time between 0.5 h and 3 h since the mixing of soybean meal flour with crosslinker solution, should be used in order to ensure the desired water resistance of plywood panels for engineered wood flooring. And an application strategy was proposed to ensure the required water resistance of plywood panels for manufacturing engineered wood flooring.

摘要

商业上应用于木基复合材料的豆粕基粘合剂 (SMA) 需要稳定的粘合性能。然而，SMA的结构和性能不如合成树脂稳定，这显着影响了它们的性能。在这项研究中，系统地研究了 SMA 随工作时间的结构-性能演变。研究结果表明，SMA 的二级结构、微观结构、交联密度、zeta 电位、氮溶解指数、粘度、木材渗透性和粘合性能随工作时间的变化很大。粘合性能的变化与 SM 颗粒在交联剂溶液中的溶解以及液态 SMA 的预固化时间增加有关，这是由于溶解的 SM 和交联剂之间的交联反应导致的。优选地，SMA 在豆粕粉与交联剂溶液混合后的 0.5 至 3 小时工作时间应使用，以确保工程木地板用胶合板具有所需的耐水性。并提出了一种应用策略，以确保制造工程木地板所需的胶合板耐水性。