木粉/废旧橡胶粉/HDPE三元复合材料热压法制备工艺

Manufacturing of wood/rubber/HDPE composites by hot pressing

木材/橡胶/塑料三元复合材料是以塑料为基体相、木材为力学增强相、橡胶为缓冲功能相制成的新型复合材料,其成型常采用挤出成型工艺,但产品的幅面尺寸较小,约束了产品在大幅面装饰领域的应用。为此,笔者以废旧橡胶粉、高密度纤维板砂光粉和高密度聚乙烯(HDPE)为主要原料,马来酸酐改性聚乙烯(MA-PE)为偶联剂,尝试采用平压法工艺生产木橡塑三元复合材料,详细考察了热压温度、热压时间对复合材料物理力学性能的影响。结果表明:当热压压力不变,温度为185℃和195℃时条件下,物理力学性能随着热压时间的延长总体上呈现增强趋势;而当热压温度升至205℃时,力学性能则显著降低。说明不同的热压温度、热压时间对木橡塑复合材料的力学性能具有显著影响。由此确定压制密度为1 000kg/m3、厚度为5mm的木橡塑三元复合材料的较优热压工艺条件为:热压温度185℃、热压时间20min,或热压温度195℃、热压时间10min。在这两种工艺条件下,产品性能较优且相近。研究表明,采用热压法生产大幅面木橡塑复合材料技术完全可行,试验结果为工业化生产实践提供了有益的参考。

Wood/robber/plastic composites （WRPC） are new type of wood-based composite material. The raw materials play different roles in the composite system. Plastic matrix functions as the ＂adhesive＂ ; wood fiber is the reinforcing component; and the rubber acts as buffer. Wood/rubber/plastic composites are often prepared using extrusion molding process. However, the small board size limits its use, especially where large area decoration is needed. In this study, wood/rubber/plastic composites were prepared using hot pressing process. The raw materials were waste rubber powder, sanding dust of high density fiberboard and high density polyethylene （HDPE）. Maleic anhydride grafted polyethylene （MA-PE） was chosen as coupling agent. The influence of press temperature and press time on the physical and mechanical properties of the composites were investigated. The results showed that, when the press temperature was 185℃ or 195℃ and the pressure was kept constant, the board properties were improved with the prolonged press time. When the temperature climbed to 205℃, the mechanical property decreased significantly. Press time and temperature showed pronounced influence on properties of WRPC. An optimized hot pressing process to prepare 5 mm WRPC with the density of 1 000 kg/m^3 is proposed as follows： The press temperature is 185℃ and the press time is 20 min, or the press temperature is 195℃ and the press time is 20 min. The products thus prepared exhibited similar good performance. It is technically feasible to produce large size WRPC using hot pressing process, and the experimental data has reference value for the full-scale production.