Altering the Hierarchical Morphology Distribution of Injection Molded Polyethylene by the Introduction of Crosslink Network and Periodical Shear  

作　　者：Zhi-hao Zhao Fei-fei Wang Man Zhou Kai-zhi Shen 张杰 

机构地区：[1]College of Polymer Science and Engineer'ing,State Key Laboratory of Polymer Materials En~neering,Sichuan University,Chengdu 610065,China

出　　处：《Chinese Journal of Polymer Science》2016年第12期1479-1489,共11页高分子科学（英文版）

摘　　要：High density polyethylene （HDPE） with moderate content of crosslink network （CPE） was successfully prepared through chemical method. Specimens for structural characterization have been molded by conventional injection molding （CIM） and pressure vibration injection molding （PVIM）. Influence of crosslink network on hierarchical morphology distribution and mechanical properties was systematically studied. Polarized light microscopy （PLM） revealed that both CIM and PVIM PE samples have a typical ＂skin-core＂ structure and the thickness of shear layer of CIM PE and PVIM CPE samples obviously increase. Scanning electron microscopy （SEM） showed that shish-kebab structures are clearly observed in shear layer of CIM CPE sample, indicating that the crosslink network can surely improve the formation of shish-kebab structures. Moreover, we suppose that shish-kebab structures emerged in shear and core layer of PVIM CPE sample. Wide- angle X-ray diffraction （WAXD） and small-angle X-ray scattering （SAXS） confirmed that more orientation and shish-kebab structures form even in core layer of PVIM CPE sample, which demonstrated that the hierarchical morphology was apparently altered by periodical shear and crosslink network. Finally, the mechanical properties revealed that this oriented structure increase the tensile strength from 31 MPa of CIM PE sample to 46 MPa of PVIM CPE sample. However, the tensile behavior tended to change from ductile fracture to brittle fracture.High density polyethylene （HDPE） with moderate content of crosslink network （CPE） was successfully prepared through chemical method. Specimens for structural characterization have been molded by conventional injection molding （CIM） and pressure vibration injection molding （PVIM）. Influence of crosslink network on hierarchical morphology distribution and mechanical properties was systematically studied. Polarized light microscopy （PLM） revealed that both CIM and PVIM PE samples have a typical ＂skin-core＂ structure and the thickness of shear layer of CIM PE and PVIM CPE samples obviously increase. Scanning electron microscopy （SEM） showed that shish-kebab structures are clearly observed in shear layer of CIM CPE sample, indicating that the crosslink network can surely improve the formation of shish-kebab structures. Moreover, we suppose that shish-kebab structures emerged in shear and core layer of PVIM CPE sample. Wide- angle X-ray diffraction （WAXD） and small-angle X-ray scattering （SAXS） confirmed that more orientation and shish-kebab structures form even in core layer of PVIM CPE sample, which demonstrated that the hierarchical morphology was apparently altered by periodical shear and crosslink network. Finally, the mechanical properties revealed that this oriented structure increase the tensile strength from 31 MPa of CIM PE sample to 46 MPa of PVIM CPE sample. However, the tensile behavior tended to change from ductile fracture to brittle fracture.

关 键 词：SHISH-KEBAB Morphology distribution Periodical shear Mechanical properties. 

分 类 号：TQ325.12[化学工程—合成树脂塑料工业]