To investigate the influence of molecular structure of isotactic polypropylene (iPP) on the crystallization behavior and mechanical properties of its β-nucleated product, in this study, four iPP samples were selected. Results of molecular structure characterizations revealed that the molecular weight of the iPP resins are close, while the average isotacticities and the isotacticity distributions of the samples are quite different from each other. Isothermal crystallization kinetics study suggested that due to their different average isotacticities and isotacticity distributions, the crystallinity difference of the four samples is as high as 5.3%, and the crystallinity of β-crystal difference is as high as 7.2%. Generally, the higher the average isotacticity of the iPP and the wider its distribution are, the stronger the β-crystallization ability of the sample is. Moreover, the mechanical measurement revealed that high average isotacticity and the wide isotacticity distribution of the iPP resulted in the strong the β-crystallization ability and thus better the toughness.

为了研究全同立构聚丙烯（iPP）的分子结构对其β成核产物的结晶行为和力学性能的影响，本研究选择了四个iPP样品。分子结构表征结果表明，iPP树脂的分子量相近，而样品的平均全同立构规整度和全同立构规整度分布却完全不同。等温结晶动力学研究表明，由于它们的平均等规度和等规度分布不同，这四个样品的结晶度差异高达5.3％，而β晶体差异的结晶度高达7.2％。通常，iPP的平均全同立构规整度越高，其分布越广，样品的β-结晶能力越强。此外，机械测量表明，iPP的平均全同立构规整度高和全同立构规整度分布导致强大的β-结晶能力，因此具有更好的韧性。