挤出共混中的高剪切应力对HDPE/滑石粉共混材料力学性能的影响

采用在材料熔融挤出共混过程中提高双螺杆挤出机螺杆转速的方法,研究了较高螺杆转速条件下双螺杆挤出机的高剪切应力对HDPE和HDPE/滑石粉材料的熔体流动速率、界面结合状况及力学性能的影响。结果表明:双螺杆挤出机的高剪切应力可促进超细滑石粉颗粒聚集体的分散、引发HDPE分子链的断链反应、引起共混材料界面结合力的加强和拉伸强度及弯曲模量的明显增大;一定量的极性烯类单体的加入有利于所形成的HDPE大分子自由基与极性烯类单体的接枝(嵌段)反应和原位增粘作用,能明显改善HDPE/滑石粉共混材料的力学性能。

Effect of High Shearing Stress During Melt Extruding on the Mechanical Properties of HDPE/Talc Blends

In this paper,the effect of high shearing stress of the twin screw extruder during melt extruding on the melt flow rate,the interfacial adhesion and mechanical properties of HDPE/Talc blends was investigated by increasing the twin screw rotation speed and changing the extruding condition.The results show that the high shearing stress of the twin screw extruder during melt extruding can accelerate the distribution of Talc particles in the matrix,induces the scission of the HDPE molecule chains and increases the interfacial adhesion and the tensile strength and flexural module of the HDPE/Talc blends.An amount of polar monomers is favorable to the reaction of grafting or blocking copolymerization of the macroradicals produced from stress-induction with the polar monomers and the in-situ improvement of interfacial adhesion and the enhancement of the mechanical properties of the HDPE/Talc blends.