PE/改性稻草复合材料光降解性研究

Study on photodegradation properties of composite materials made from PE and modified rice straw

农作物秸秆与塑料的共混材料,是一类新的木塑复合材料(WPC).光降解性是WPC的主要特征之一.本文以低密度聚乙烯(LDPE)为基体,分别与天然稻草和环氧氯丙烷改性稻草共混制成稻草/PE复合材料,在耐候试验箱中进行加速老化试验,研究材料的光降解性能.经过576 h老化,PE/天然稻草复合材料失重率约0.27%,PE/改性稻草复合材料失重率为0.22%～0.27%,两种材料的失重率无明显差异.老化前,PE/改性稻草复合材料的力学性能优于PE/天然稻草复合材料,而老化后,前者的力学性能差于后者.拉伸断面SEM照片表明,PE在改性界面包覆性好,改性稻草在PE基体中分布均匀,紫外光对PE/改性稻草复合材料的破坏更严重,力学性能下降更显著.

Blend materials made from crop straws and plastics are recently developed wood plastic composite(WPC) materials.Photo-degradation is one of dominant features of WPCs.In the present work,as a matrix,the low density polyethylene was mixed with the natural rice straw and the rice straw modified by the epichlorohydrin,to produce the composite materials.The accelerated photo-degradation tests were carried out in the QUV/basic weathering test box.After aging for 576 h,weight loss ratio for PE/natural rice straw composites were about 0.27%,and those for PE/modified rice straw composites were in the range from 0.22% to 0.27%,showing no significant difference between two kinds of materials.Before aging test,mechanical properties of PE/modified rice straw composites were better than those of PE/natural rice straw composites.After aging test,contrary results were obtained.SEM patterns of tensile fractures for different materials showed that polyethylene formed complete coatings on modified rice straw fibres,and modified rice straw distributed more evenly.It also could be seen that ultraviolet rays resulted in more serious damage on PE/modified rice straw composites.That was why the mechanical properties of PE/modified rice straw composites reduced more notably..