聚丙烯结构形态对性能的影响

用红外光谱、动态粘弹谱、透射电镜、X光衍射仪、DSC、偏光显微镜和机械力学性能测试仪等手段对均聚、嵌段共聚、无规共聚PP进行了结构、形态与性能关系的研究。结果表明,嵌段共聚物中乙烯在红外谱图中显示两个特征峰,而无规共聚物中乙烯只出现—个特征峰。研究还证明,PP嵌段共聚物是PP、PE、EPR多元组分的共混物。PE包含在EPR中以球形无规地分散在PP基体中。EPR的含量是提高PP共聚物冲击性能的决定因素。无规共聚物形态接近均相体系,其冲击强度小于嵌段共聚物而大于均聚物。

The Influence of Morphology of PP on Its Mechanical Properties

The relationship between morphological structure and mechanical properties of the PP in the form of homopolymer, block copolymer and random copolymer has been investigated by means of IR, DSC, XRD, TEM, polarized light microscope, dynamic viscoelastomer and the instrument used for measuring the mechanical properties. The results have shown that there are two key bands in the infrared absorption spectrum of ethylene in the block copolymer while there is only one in the corresponding spectrum of the ethylene in the random copolymer. The investigation has demonstrated that the PP copolymer is actually the multlcomponent blend of PP, PE, and EPR, and furthermore, the PE is wrapped in the EPR and dispersed randomly in the shape of sphere in the PP matrix. The content of EPR could be regarded as a crucial factor for improving the impact property of the PP copolymer. The morphological structure of the random copolymer is similar to that of homogeneous system. The impact strength of the random copolymer is lower than that of block copolymer, but higher than that of homopolymer.