【摘要】 采用四种方法(DSC法、压片法、热膨胀法、挤出法)研究了聚苯乙烯和聚甲基丙烯酸甲酯类无定形高聚物的液-液转变温度。确认了聚苯乙烯和聚甲基丙烯酸甲酯类高聚物液-液转变温度的存在,且不同方法所得到的液-液转变温度基本上吻合。在挤出法的研究中,发现在此温度以上和以下,高聚物熔体的粘度和挤出物胀大有很大差别,由此预测在液-液转变温度以上和以下加工出的制品的最终性能有重大差别。更多还原

【Abstract】 Four methods (DSC, compression molding, thermal expansion, extrudate swell) are used to observe the liquid-liquid transition temperature of polystyrene and poly (methyl-methacrylate) . The results of these experiments are corroborating. The liquid-liquid transition temperature is a material intrinsic parameter that is very important in the processing of polymers. At this transition temperature there is a abrupt change in the flow properties of the melt, implying that processing above and below this transition temperature gives rise to products with very different end use properties.更多还原