挤出共混中的高剪切应力对PP-HDPE-滑石粉共混材料力学性能的影响

采用提高双螺杆挤出机螺杆转速的方法,研究了双螺杆挤出机的高剪切应力作用对聚丙烯(PP)、PP-滑石粉和PP-高密度聚乙烯(HDPE)-滑石粉共混材料力学性能的影响.结果表明:双螺杆挤出机的高螺杆转速、高剪切应力作用,可促进材料中滑石粉颗粒的均匀分散、促进HDPE均匀分散于PP基体的乙丙共聚物的相态之中,可引起PP或HDPE的断链反应、引起HDPE大分子自由基与PP基体中的EPR相以及与滑石粉表面偶联助剂之间的结合反应,引起共混材料缺口冲击强度的显著增大;少量极性烯类单体的加入和较低的挤出反应温度条件(180℃)有利于形成的大分子自由基与极性烯类单体的接枝、嵌段反应、界面间的偶联结合反应及其原位增粘作用,并引起PP-HDPE-滑石粉共混材料缺口冲击强度的进一步增大.

Effect of high shearing stress during melt extruding on the mechanical properties of PP-HDPE-Talc fillers blends

The effect of high shearing stress of the twin screw extruder on the mechanical properties of PP, PP-Talc and PP-HDPE-Talc blends was investigated by increasing the twin screw rotation speed and changing the extruding temperature. The results show that the high shearing stress of the twin screw extruder during melt extruding can accelerate the distribution of Talc particles and HDPE particles in the matrix, induce the scission of PP and HDPE molecule chains, and lead to the reactions of HDPE macroradicals with EPR chain segments in PP molecules and the coupling reaction of the macroradlcals with the interfacial surface of Talc particles, which obviously increase the impact strength of the PP-HDPE-Talc blends. Both the addition of polar monomers and the lower extruding temperature condition are favorable to the reaction of lar monomers, the in-situ improvement of the PP-HDPE-Talc blends. grafting or blocking copolymerization of the macroradicals with the pointerfacial adhesion and the enhancement of the impact strength of the