高韧性聚乙烯合金的制备与性能

Preparation and Investigation of Polyethylene Alloy with High Toughness

采用氢化苯乙烯-丁二烯-苯乙烯共聚物(SEBS)、二元乙丙橡胶(EPR)、三元乙丙橡胶(EPDM)及乙烯-辛烯共聚物(POE),分别与高密度聚乙烯(HDPE)以不同比例在双螺杆挤出机中熔融共混,制备高韧性聚乙烯合金。冲击测试表明,在四种共混物中,HDPE/POE具有较佳的力学性能;Vu-Khanh方程表明,Gi与冲击性能有很好的对应关系;扫描电镜表明,弹性体在HDPE中有很好的分散,橡胶粒径较小,分散均匀;形变区观察显示,纯HDPE为脆性断裂,而HDPE/弹性体断裂表面发生塑性形变,发生剪切屈服,呈明显的韧性断裂。

Four kinds of thermoplastic elastomers, hydrogenated styrene-butadiene-styrene copolymer （SEBS）, ethylene propylene rubber（EPR）, ethylene-propylene-diene rubber （EPDM） and ethylene-octene copolymer （POE）, were blended with high-density polyethylene in a different proportion by the twin-screw extruder. Impact test results show that HDPE/POE blend displays better mechanical properties in the four blends. Vu-Khanh plot shows that： Gi value is corresponding with the impact strength. Scanning electron microscope （SEM） shows that the elastomers disperse in HDPE uniformly and rubber particle size is small. Fracture surface observation indicates that pure HDPE fractures in brittle mode, and plastic deformation of HDPE blends takes place obviously. Shear yielding of HDPE is the major deformation mechanism.