不同聚乙烯基塑木复合材料的性能

Comparative Analysis on Properties of Plastic-w ood Composite Based on Different Kinds of Polyethylene

采用注塑工艺制备高密度聚乙烯(HDPE)基、低密度聚乙烯(LDPE)基及HDPE、LDPE混合基塑木复合材料(WPC),同时制备了纯HDPE及LDPE试样,对比研究了不同试样的吸水率、吸水尺寸稳定性、受热尺寸稳定性、耐冷热循环性、抗低温冻融性及抗冲击性能。结果表明,纯塑料的吸水率及吸水后尺寸变化率均较低,但是,受热后正反面尺寸变化相差较大,冷热循环后尺寸变化较大;当形成WPC后,试样的吸水率及吸水后尺寸变化率显著升高,其中,HDPE与LDPE混合基体的WPC的吸水率最高,其值为1.57%,宽度和厚度尺寸变化率分别为0.11%和1.08%;受热后,正反面尺寸变化率差值减小,耐冷热循环能力得到显著提升;HDPE及其WPC的弯曲强度与LDPE及其WPC相比较高,但是,后者的抗冻融性能及抗冲击性能与前者相比较好。

Plastic-wood composite specimens based on high density polyethylene(HDPE),low density polyethylene(LDPE)and their mixture were prepared by injection molding process respectively,at the same time,pure HDPE and LDPE specimens were also prepared.The water uptake,dimensional stability after water immersion and heating,properties of resistance to thermal cycling and low temperature freeze-thaw,and impact strength of different specimens were investigated comparatively.The results showed that,pure plastics had least water uptake and dimensional change after water immersion,but the difference in dimensional changes of two sides of the specimens were greater after heating,and also the dimension changed greater after thermal cycling.For WPC,the water uptake and dimensional change after water immersion were increased obviously,especially for WPC based on HDPE and LDPE mixture,it had the greatest water uptake,as much as 1.57%,and the change in width and thickness were 0.11%and 1.08%respectively.The difference between the dimensional changes in two sides of WPCs after heating were decreased from those of pure plastics,the resistance to low temperature freeze-thaw of WPCs were improved obviously,HDPE and its WPC had greater flexural strength while poorer impact strength than LDPE and its WPC.