【摘要】 采用自制的剪切拉伸双向复合应力场挤管装置,在常规工艺条件下生产了3种双向自增强的高密度聚乙烯(HDPE)管材。当剪切套转速控制为20 r/min时,牌号为2480、HD4801EX和5421B的HDPE挤出的管材周向拉伸强度与常规挤出管材相比,依次增加24.8%、41.7%和21.5%,而轴向拉伸强度的增加幅度依次为12.7%、16.8%和10.4%。通过SEM、WAXD和DSC测试手段对HDPE(2480)试样进行微观结构分析,发现其经过复合应力场后管材内部的微观结构仍是球晶,但晶体尺寸有所减小,熔融峰升高,结晶度增大。同时,管材周、轴两向的衍射强度都增强,分子链取向有所增强。更多还原

【Abstract】 Using self-made shearing-drawing biaxial complex stress field die,three types of biaxially self-reinforced high density polyethylene(HDPE) pipe were extruded under traditional process conditions.Compared to regularly extruded pipes,the circumferential tensile strength of three types of HDPE(2480,HD4801EX and 5421B) was increased by 24.8 %,41.7 % and 21.5 %,respectively when the rotational speed of shear casing was 20 r/min,while the axial tensile strength increased by 12.7 %,16.8 % and 10.4 % respectively.The samples of HDPE(2480) were characterized by SEM,WAXD and DSC.It was found that the microstructure of self-reinforced pipes was still spherocrystal,but crystallite sizes decreased,melting points drifted to high temperature and the degree of crystallinity increased under complex stress field.Meanwhile,the diffraction intensity of biaxial self-reinforced pipe increased and the molecular chain orientation increased too.更多还原