共混方式对PP／UHMWPE合金的力学性能的形态结构的影响

采用四螺杆挤出机和双螺杆挤出机将ＰＰ和ＵＨＭＷＰＥ挤出共混制成ＰＰ／ＵＨＭＷＰＥ合金,并测试其力学性能,用ＳＥＭ和ＤＳＣ对两种共混方式所制备的合金的亚微形态和热性能进行了考察。发现四螺杆挤出机能将ＵＨＭＷＰＥ均匀地分散在ＰＰ基体中,使合金的缺口冲击强度和其它力学性能得到显著的提高,其冲击样条断裂面上呈现细点状结构;同时在合金中,ＵＨＭＷＰＥ与ＰＰ形成共晶结构,并导致ＵＨＭＷＰＥ熔点下降;表明ＵＨＭＷＰＥ以准分子水平分散在ＰＰ基体中,形成“线性互穿网络”结构。而双螺杆挤出机对ＰＰ／ＵＨＭＷＰＥ合金的共混效果却不佳,所制备的合金的力学性能不能得到有效的提高,冲击样条断口呈现典型的脆性断裂行为;合金中也不存在共晶结构。证明对于ＰＰ／ＵＨＭＷＰＥ合金,四螺杆挤出机比双螺杆挤出机具有更好的共混效果。

EFFECT OF BLENDING METHODS ON MECHANICAL PROPERTY AND MORPHOLOGY STRUCTURE OF PP/UHMWPE BLENDS

In this study,the blends of PP and UHMWPE were prepared by the four-screw extruder and twin-scres extruder,and the mechanical,morphological and thermal properties of these two blends were investigated.For the material blended by the four-screw extruder,a 15% content of UHMWPE corresponded to a maximum Izod impact strength,and its fracture behavior showed a little spots structure inferring a "linear interpenetrating nework"existed in PP matrix.But the blends prepared by the twin-screw extruder were shown brittleness.A co-crystal structure was found in PP/UHMWPE blends prepared by the four-screw extruder through DSC investigation,and not in that by the twinscrew extruder.Mechanical,morphological and thermal properties demonstrated that melt blending by the four-screw extruder was a better procesing method to PP/UHMWPE blends than that the by twinscrew extruder