PP/PA66原位复合材料的增强和增韧效应

THE REINFORCING AND TOUGHENING EFFECTS OF PP/PA66 in-situ COMPOSITES

用挤出 拉伸 注塑法制得了增强又增韧的PP PA66原位复合材料 ,以未经拉伸的普通共混材料作对照 ,研究了PA66质量含量 (cd)对材料相形态和力学性能的影响及其作用机制 .结果表明 ,当cd 由 0 %增至2 0 %时 ,原位形成的PA66纤维数量增多 ,纤维直径及其分散性以cd =1 5 %为界先减小后增大 ,残留的PA66粒子数也增多 ;纤维数量的增多和纤维网络的发展导致材料冲击强度持续增高 ;纤维及粒子对基体的增刚作用使材料杨氏模量增高趋于极限值 ;受分散相对基体增强效应和两相弱粘结界面缺陷效应的综合影响 ,材料的拉伸强度以cd =1 5

The reinforced and toughened PP/PA66 in-situ composites were prepared via an extrusion-drawing-injection molding method. The influence of PA66 weight content (c(d)) on the phase morphology and mechanical properties of composites together with their functional mechanisms were investigated by contrast to the normal blended materials without drawing. The results show that as c(d) increases from 0 to 20%, the number of PA66 fibers in-situ formed rises whereas their diameter and its dispersity decrease till c(d) = 15% and then enhance. Simultaneously, the number of unfibrilized PA66 particles also enlarges. The continuous increment of impact strength of composites, which is superior by 65% to that of pure PP at c(d) = 20% can be attributed to the increased number of fibrils and the formation of fibrillar network. The ridigized effects of fibrils and particles on the matrix contribute to the increased Young's modulus of composites up to a plateau level,which is higher by 36% than that of pure PP at c(d) = 15% The tensile strength of composites increases till c(d) = 15% where its value is greater by 10% than that of pure PP,and then drops off. This is the counterbalanced effect of the reinforced effect of the dispersed phase on the matrix and the flaw effect at the weak interfaces between two phases.