ABSTRACT

A novel biomass-based wood adhesive was prepared with commercial Mimosa tannin extract and glycerol diglycidyl ether (GDE) by convenient mechanical mixing. GDE served as the crosslinker of the tannin without any aldehyde addition yielding hardened three-dimensional networks. Different weight ratios of tannin/GDE were investigated by a number of techniques to determine their influence on final properties. The results showed that a non-hydrolysable ester bonds can be formed between the epoxy groups of GDE and hydroxyl groups of tannin, this being the critical factor for the good water resistance obtained by the wood adhesives prepared. Moreover, the dry and wet shear strength exhibit positive correlation with the proportion of GDE added. Even at a relatively small proportion of GDE (33% of the weight of dry tannin), the dry and 24 h cold water shear strengths of the bonded plywood satisfied the requirements of relevant standard (GB/T 9846–2015, ≥0.7 MPa). The thermal stability of the tannin-based wood adhesive so prepared progressively improved with the increasing proportion of GDE.

摘要

通过便利的机械混合，用市售含羞草单宁提取物和甘油二缩水甘油醚（GDE）制备了一种新型的基于生物质的木材胶粘剂。GDE用作单宁的交联剂，不添加任何醛，可产生硬化的三维网络。通过多种技术研究了单宁/ GDE的不同重量比，以确定它们对最终性能的影响。结果表明，在GDE的环氧基和单宁的羟基之间可以形成不可水解的酯键，这是制备的木材粘合剂获得良好耐水性的关键因素。此外，干和湿剪切强度与添加的GDE的比例呈正相关。即使GDE的比例相对较小（单宁干重的33％），胶合板的干，24 h冷水剪切强度满足相关标准（GB / T 9846-2015，≥0.7MPa）的要求。如此制备的基于单宁的木材粘合剂的热稳定性随着GDE比例的增加而逐渐改善。