自增强塑料的性能与工艺初探

SELF-REINFORCEMENT OF PLASTICS PROPERTIES AND PROCESSING

本文简要地研究讨论了热致液晶塑料和聚烯烃塑料的自增强力学性能及其工艺方法,指出了聚合物材料的工艺方法与力学性能之间的密切关系,通俗地介绍了分子自增强塑料的结构特点,解释了这类材料能够实现自增强的材料学基础。

The thermotropic liquid-crystal polymers are notable forhigh-temperature performence, self-reinforcement, and an ability to beprocessed by conventional processing equipments of plastics. By theinvestigation it has been shown that the quality of the extrudate can bechanged by controlling extrusion conditions, for example melttemperature. A temperature-window has been found. Because of thedifferent orientations, the anisotropy and the skin/core properties thetensile strength and deformation of parts made from this family ofself-reinforcing polymers under discussion have been found to be dependentstrongly of the flow conditions of the melt.The inereasement of the stiffness and strength of the self-reinforcedpolyethylenes by injection molding changes with the parameters of theinjection, the most notable being the geometrical boundary conditionsfor melt flow, melt temperature and holding pressure. Other parameters,such as the injection velocity and the mold temperature have a clearlyless influence. The mechanical properties as a function of the holdingpressure indicate a linear dependence.