具有高界面压应力的高分子共混物Ⅱ.拉伸过程中形态演化与增强机理

研究了聚对苯二甲酸乙二醇酯(PET)/聚乙烯(PE)和聚碳酸酯(PC)/PE共混物在拉伸过程中形态的演化和增强机理.结果表明,高界面压应力是共混物在基体加工温度成型时,从成型温度冷却到室温过程中基体收缩比分散相大产生的;两种共混物在拉伸中有不同的形态演化过程:PC粒子原位形成了微纤,粒子与基体间没有明显的界面滑动,而PET粒子只产生较小的塑性变形,成为椭球状粒子,粒子与界面间存在滑动.PC对基体PE的增强效果比PET的更好,因为PC/PE共混物拉伸过程中形成了良好增强作用的原位微纤.在拉伸过程中,PET/PE试样的细颈在靠近非浇口端形成,并从此扩展开.部分拉伸后,PC/PE试样比PET/PE试样的弹性回复大,回复到平衡状态时间长,这是两种共混物分散相变形机理不同引起的.

Polymer blends with high interfacial compressive stress:morphology evolution during elongation and reinforcing mechanism

The morphology evolution during elongation of the poly(ethylene terephthalate) (PET)/polyethylene (PE) and polycarbonate (PC)/PE blends with high interfacial contact (pseudo-adhesion) was examined. The morphological observation indicates that for PC/PE blends, numerous PC microfibrils are in-situ formed, while for PET/PE blends, slippage takes place between the PET particles and the matrix. This can successfully explain the mechanism of the different reinforcement of PET and PC on PE. Moreover, the macroscopic morphology development of both blends during tensile testing is also quite different. For the PET/PE blend, the necking first occurs on one point close to the non-gate end of the specimen; subsequently the necking (cold drawing) spreads uniformly from thispoint. For the PC/PE blend, the necking zone and its extension are irregular, and generally, the whole tested zone is elongated gradually.