相对分子质量及立构缺陷分布对β晶聚丙烯结晶及形态的影响

发布时间：2018-04-05 09:48

本文选题：等规聚丙烯　切入点：立构缺陷分布　出处：《高分子材料科学与工程》2017年05期

【摘要】：制备了具有不同立构缺陷分布均匀性、不同相对分子质量的系列等规聚丙烯(iPP)样品,利用差示量热扫描仪、广角X射线衍射仪、扫描电子显微镜等深入研究了双组分β晶成核剂作用下,iPP的相对分子质量、立构缺陷分布均匀性对其多晶型行为、非等温结晶动力学行为,尤其是β晶含量、形态和热稳定性的影响。结果表明,立构缺陷分布的均匀性决定了iPP结晶温度的高低;而立构缺陷分布均匀性与相对分子质量都是结晶活化能的重要影响因素。在熔融方面,相对分子质量和立构缺陷均匀性都是影响β晶含量、β晶热稳定性的重要决定因素。相对分子质量越低、立构缺陷分布越不均匀,越不利于形成高含量β晶;然而,立构缺陷分布越不均匀,相对分子质量越高,越容易形成热稳定性高的β晶。上述研究结果表明,在双组分β晶成核剂作用下,iPP的相对分子质量和立构缺陷均匀性对iPP的β结晶具有不同的影响特征,因此在实际研究及加工过程中需综合考虑。
[Abstract]:A series of isotactic polypropylene (IPP) samples with different structural defects and different molecular weights were prepared. The samples were obtained by differential calorimeter and wide-angle X-ray diffractometer.Scanning electron microscopy (SEM) has been used to study the relative molecular weight, the distribution uniformity of orthotropic defects and the non-isothermal crystallization kinetics, especially the 尾 -crystalline content, of PP under the action of two-component 尾 -crystal nucleating agent.Effects of morphology and thermal stability.The results show that the homogeneity of the distribution of orthotropic defects determines the crystallization temperature of iPP, and that the uniformity of the distribution of orthotropic defects and the relative molecular weight are important factors affecting the activation energy of crystallization.In the aspect of melting, the relative molecular weight and the homogeneity of the vertical defects are the important determinants of the content of 尾 -crystal and the thermal stability of 尾 -crystal.The lower the relative molecular weight, the more uneven the distribution of orthotropic defects is, which is not conducive to the formation of high content 尾 crystals. However, the more uneven the distribution of orthotropic defects is, the higher the relative molecular weight is, and the easier it is to form 尾 crystals with high thermal stability.The above results show that the relative molecular weight and the homogeneity of orthotropic defects of iPP have different effects on the 尾 -crystallization of iPP under the action of two-component 尾 -crystal nucleating agent. Therefore, it is necessary to consider comprehensively in the process of practical research and processing.
【作者单位】：重庆交通大学土木工程学院;重庆市智翔铺道技术工程有限公司;招商局重庆交通科研设计院有限公司;四川大学高分子研究所高分子材料工程国家重点实验室;
【基金】：国家自然科学基金资助项目(NSFC 51202214) 重庆市杰出青年基金资助项目(cstc2014jcyjjq30002)
【分类号】：O632.12

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