亚临界流体挤出法制备高密度聚乙烯/木粉复合材料

Fabrication and Properties of HDPE/Wood Flour Composites in Subcritical Fluid

采用亚临界流体挤出法制备高密度聚乙烯(HDPE)/木粉复合材料,研究了亚临界流体种类(去离子水、正丙醇和乙醇)与温度对木塑复合材料(WPC)综合力学性能的影响。实验利用傅立叶变换红外光谱、差示扫描量热分析和扫描电镜分别对复合材料的化学组成、热变形温度和界面形貌作了相应的研究。结果表明,亚临界流体的高温高压可以对木纤维起到很好的溶胀作用,一定程度上打破了木素、半纤维素对纤维素的包裹作用,明显促进基体与木纤维之间的机械捏合与酯化反应,增加界面强度。在亚临界流体条件下,尤其在亚临界乙醇条件下,木粉在HDPE树脂基体中具有优异的分散性,拉伸断面处的断裂形式主要以基体与纤维断裂为主,说明HDPE/木粉的WPC具有较好的界面结合强度。

HDPE/wood flour composites were fabricated in subcritical fluid to study the effect of subcritical fluid types （deionized water, n-propanol and ethanol） and temperature on mechanical properties of wood plastic composites （WPC）. The chemical composition of WPC was evaluated by FT-IR; the thermal transition temperature and microstructure were measured by DSC and SEM. The results indicate that subcritical fluids at high temperature and high pressure can increase the swelling effect to wood fiber and partly break down the package of lignin and hemicelluloses to cellulose, thus obviously increase the interracial adhesion between the wood fibers and the matrix by promoting mechanical kneading and esterification. Under the condition of subcritical fluids, especially in subcritical ethanol, the wood flour has excellent dispersion in the resin, and the breakage form of the fracture section is mainly based on the matrix and wood fiber, which indicate that WPC has good interracial adhesion.