在低压动态注射过程中LDPE对HDPE自增强的增韧改性

Toughness Improvements ofSelfReinforce HDPE with the Addition of LDPEin the Course of Low Pressure Dynamic Injection Molding

本文研究了ＬＤＰＥ在低压动态保压注射过程中对ＨＤＰＥ的自增强的增韧改性体的结构与性能。扫描电镜观察到ＨＤＰＥ与ＬＤＰＥ动态保压注射试样的拉伸断面呈多层断裂结构，剪切层与芯层的断裂面韧性成分显著增加，同纯ＨＤＰＥ自增强试样相比，拉伸强度（ＨＤＰＥ／ＬＤＰＥ，８０／２０）没有下降，韧性却显著增加，在一定程度上克服了ＨＤＰＥ自增强后呈脆断的缺点。试验表明，试样剪切层强度的提高是由于大分子沿流动方向高度取向所致，剪切层结晶度降低，内部呈透明状态，晶粒细化，试样内部芯层呈韧性断裂、强度较低，晶粒粗大。

お? HDPE was blended with LDPE in the selfreinforcement of HDPE through low pressure dynamic injection molding. Scanning electronic microscopic observations revealed that the tensile failure sections exhibited multilayer fractures, whereas the transverse section and the inner core were intensively fractured, apparently due to toughness failure manner. The tensile properties of 80/20 by weight blending of HDPE/LDPE were found to be comparable to that of a 100% selfreinforcing HDPE, while significant increases in toughness was noted. In addition, inherent brittleness of 100% selfreinforcing HDPE was somewhat suppressed by the addition of LDPE. It was also noticed that the strength properties along the shear section of the blended sample were much improved. It was believed that this was resulted from the predominating orientation of the macromolecules along the flow direction. Lower crystallinity in the shear section was observed. The inner core of the blended sample, however, was composed of coarse crystals and was weak in strength.