高强度木单板/异氰酸酯复合材料制备及性能优化

Preparation and performance optimization of high-strength wood veneers/poly-isocyanate composites

通过脱除木质素的方法对木材进行前处理是制备高强度木基复合材料的一种重要手段,然而,脱除木质素过程中会产生大量废液,且不利于工业化应用。在当前“双碳”目标以及绿色发展的背景下,探究一种低碳环保、简单高效的高强度木基复合材料的制备方法对提升木材附加值显得尤为重要。基于此,以桦木单板和聚合二苯基甲烷二异氰酸酯(pMDI)为原材料,采用正交试验研究热压温度、热压时间以及pMDI添加量对高强度木单板/异氰酸酯复合材料(pMDI-WC)的力学性能、耐水性和表面颜色的影响。结果表明,热压温度、热压时间和pMDI添加量对pMDI-WC的力学性能、耐水性和表面颜色均具有显著的影响。厚度为6 mm的pMDI-WC最佳热压温度、热压时间和pMDI添加量分别为170℃、20 min和10%,在最优工艺条件下制备出具有优异力学性能的pMDI-WC,其弯曲强度和拉伸强度分别是473.59和408.56 MPa。在热压温度180℃、热压时间20 min、pMDI添加量20%的条件下,pMDI-WC的耐水性最优。pMDI-WC不仅具有轻质高强特性,而且制备工艺简单、绿色环保,这对提高木材的高附加值利用和复合材料的绿色发展具有重要意义。

The pretreatment of wood by removing lignin is an important method to prepare high-strength wood-based composites.However,the process of delignification would generate a large amount of waste liquid and is not conducive to industrial applications.In the context of the current “Dual Carbon” goal and green development,it is particularly important to explore a low-carbon,environmentally friendly,simple and efficient preparation method for high-strength wood-based composites to improve the high value-added utilization of wood.Based on this,birch veneer and polymerized diphenylmethane diisocyanate(pMDI) were used as raw materials in this study.The effects of the hot-pressing temperature,hot-pressing time and the amount of pMDI on the mechanical properties,water resistance and surface color of pMDI-WC were investigated by the orthogonal experiment.The orthogonal experiment results showed that the hot-pressing temperature,hot-pressing time and the addition amount of pMDI have significant effects on the mechanical properties,water resistance and surface color of pMDI-WC.The optimal hot-pressing temperature,hot-pressing time and pMDI addition amount of pMDI-WC were 170 ℃,20 min and 10% with a sample thickness of 6 mm,respectively.The pMDI-WC with excellent mechanical properties was prepared under the optimal process conditions,and its flexural strength and tensile strength were 473.59 and 408.56 MPa,respectively.The pMDI-WC had the best water resistance under the conditions of the hot-pressing temperature of 180 ℃,hot-pressing time of 20 min and pMDI addition of 20%.The pMDI-WC has the characteristics of light-weight and high-strength,and its preparation process is simple and green,which is of great significance to improve the utilization of wood with high added value and the green development of composite materials.