Chen Mingsong, Zhang Yi, Li Yue, Shi Sheldon Q, Li Jianzhang, Gao Qiang, Guo Hongwu
MOE Key Laboratory of Wooden Material Science and Application, Beijing Forestry University, No.35 Tsinghua East Road, Beijing 100083, China.
College of Engineering Department of Mechanical and Energy Engineering, University of North Texas, 3940 North Elm street, Suite F101P, Denton, TX 76207-7102, USA.
Polymers (Basel). 2020 Mar 31;12(4):758. doi: 10.3390/polym12040758.
Bio-based adhesives have low water resistance and they are less durable than synthetic adhesives, which limits their exterior applications. In this study, a bio adhesive was developed from soybean meal and larch tannin that was designed for exterior use. Phenol hydroxymethylated tannin oligomer (PHTO) was synthesized and then mixed with soybean meal flour in order to obtain a soybean meal-based adhesive (SPA). The results showed that the moisture absorption rate, residual rate, and solid content of SPA with 10 wt % PHTO (mass ratio with respect to the entire adhesive) were improved by 22.8%, 11.6%, and 6.8%, respectively, as compared with that of pure SPA. The wet shear strength of plywood with SPA with 10 wt % PHTO (boiling in 100 °C water for 3 h) was 1.04 MPa when compared with 0 MPa of pure SPA. This met the bond strength requirement of exterior-use plywood (GB/T 9846.3-2004). This improved adhesive performance was mainly due to the formation of a crosslinked structure between the PHTO and the protein and also PHTO self-crosslinking. The formaldehyde emission of the resulting plywood was the same as that of solid wood. The PHTO-modified SPA can potentially extend the applications of SPAs from interior to exterior plywood.
生物基胶粘剂的耐水性较低，且不如合成胶粘剂耐用，这限制了它们的外部应用。在本研究中，开发了一种由豆粕和落叶松单宁制成的生物胶粘剂，设计用于外部用途。合成了酚羟基甲基化单宁低聚物（PHTO），然后将其与豆粕粉混合，以获得基于豆粕的胶粘剂（SPA）。结果表明，与纯SPA相比，含10 wt% PHTO（相对于整个胶粘剂的质量比）的SPA的吸湿率、残留率和固含量分别提高了22.8%、11.6%和6.8%。含10 wt% PHTO的SPA胶合板（在100℃水中煮沸3小时）的湿剪切强度为1.04 MPa，而纯SPA为0 MPa。这满足了外用胶合板的粘结强度要求（GB/T 9846.3-2004）。这种胶粘剂性能的改善主要归因于PHTO与蛋白质之间形成了交联结构以及PHTO的自交联。所得胶合板的甲醛释放量与实木相同。PHTO改性的SPA有可能将SPA的应用范围从室内胶合板扩展到室外胶合板。
