1673-159X

CN 51-1686/N

等规聚丙烯中高性能晶体结构调控的研究进展

The Research Progress of Tailoring High-performance Crystalline Structures in Isotactic Polypropylene

  • 摘要: 等规聚丙烯(iPP)是目前世界上用量最大的通用塑料之一,提高其综合力学性能具有重要意义。根据iPP的同质多晶和对加工环境的敏感特性,调控iPP形成β晶型,以及诸如串晶等各向异性的晶体形态,是实现iPP自增韧和自增强的重要途径。近年来,关于iPP β晶型的获得和晶体形态的可控设计已有诸多研究,其调控方法主要是对加工应力场、温度场和异相成核物质的设计。在逐渐增强的应力场和温度场作用下,iPP的晶体结构将从α球晶富集向β晶富集再向高度有序α串晶富集的方向进行转变。最新的研究成果表明,通过在流动场中添加纤维状β成核剂,可实现有序β型片晶的富集。基于此,本文着重从iPP β晶型和晶体形态调控两个方面,对相关机制和近年的研究情况进行总结和介绍。

     

    Abstract: Isotactic polypropylene (iPP) is one of the general plastics in the world. Improving the comprehensive mechanical properties of iPP is of great importance. On the basis of understanding the polymorph phenomenon and the structural sensitivity to processing conditions of iPP, it is a key way to realize the self-toughening and self-enhancing of iPP via controlling the condensed structure to appear as β-modified crystals and anisotropic crystals like shish kebab. In recent years, lots of research related to the cultivating methods of β-form iPP and the design of iPP crystalline morphology have been carried out, and the approaches applied in this area are mainly about the adjusting of processing stress field, processing temperature field and heterogeneous nucleators. Under the conditions of increasingly strengthened stress and temperature fields, the crystalline structures of iPP incline to transforming from rich α-modified spherulites to rich β-form crystals and to rich α-form shish kebab. Moreover, recent research has verified that the addition of fibrous β nucleating agents, can promote the drastic increment of orderly-stacked β lamellas during flow forming process. Thus, this paper aims to introduce and summarize the recent progress and theories corresponding to the tailoring of β-form crystals and crystalline morphologies of iPP.

     

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