高流动抗冲共聚聚丙烯专用料的结构与性能分析

Study on Structure and Properties of Propylene Copolymers with High Impact Strength and High Flowability

采用核磁共振、动态力学分析、差示扫描量热、流变性能等测试方法对国内外几种高流动抗冲共聚聚丙烯的力学性能与加工性能进行了分析。结果表明,1#样品具有较高的乙烯含量,等规度较高,二甲苯可溶物较低,均聚相与共聚相具有较好的相容性,具有最好的综合力学性能。3#样品的PE结点含量和乙烯含量均较高,因而具有最高的冲击强度。4#、5#样品具有较宽的相对分子质量分布,在高剪切速率下具有较好的加工性能。高流动抗冲共聚聚丙烯专用树脂中应含有较多的乙丙橡胶链段,均聚相要具有较高的等规指数,两相相容性要好,且相对分子质量分布要稍宽,这样才能具有良好的加工性能,同时可以提高成型制品的尺寸稳定性。

Several propylene copolymers with high impact and high flowability were characterized using nuclear magnetic resonance, dynamic mechanical analysis, differential scanning calorimeter, and rheological properties. Sample 1^# had higher ethylene content, higher isotacticity and lower xylene solubility, the homopolymer and copolymer phases showed good compatibility, and provided the best comprehensive mechanical properties. Sample 3^# had higher content of PE nodes and ethylene, so it possessed the highest impact strength. SampLe 4^#and 5^# had a wide molecular weight distribution and displayed good processing property at high shear rates. The comparison showed that propylene copolymers with high impact strength and high flowability should contain a high fraction of ethylene propylene rubber segments, a high isotactic index in the homopolymer phase, and a good compatibility between the two phases. Molecular weight distribution should be moderately wide, so that good processing behavior could be obtained, and dimensional stability of the products could be increased.