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一、前言研究等规聚丙烯(IPP)的超分子结构,是目前引人注目的课题之一.等规聚丙烯熔体的结晶过程,因受结晶温度、外加物质等的影响,常会形成不同类型的晶体结构,例如单斜晶系,六方晶系,拟六方晶系等.它们依次称α-型,β-型,最后一种(拟六方晶系)因尚未完全查明其晶体结构,暂称“急冷晶态”.由于α-型较β-型结构紧密,而且在一般情况下,IPP 中以α-型为主,所以材料的密度较大,有较高的热稳定性.在IPP 制品中,视加工条件(挤出、注射成型的情况等)的不同,常伴随有α-晶型与β-晶型共存的现象.当样品受到外力作用或热影响,其中的β-晶型便会转变为α-晶型.这时晶体内将会产生细微的裂纹与洞穴.
I. INTRODUCTION It is one of the most attractive topics to study the supramolecular structure of isotactic polypropylene (IPP). The crystallization process of isotactic polypropylene melt is often different due to the influence of crystallization temperature and other substances Type of crystal structure, such as monoclinic system, hexagonal system, quasi-hexagonal system, etc. They are in turn called α-type, β-type, the last (quasi-hexagonal) because the crystal structure has not been fully identified, Temporarily called “quench the crystalline state.” As the α-type structure is more than β-type, and in general, IPP to α-based, so the material density, high thermal stability. IPP products, depending on the processing conditions (extrusion, injection molding, etc.) are different, often accompanied by α-crystal and β-crystal coexistence phenomenon.When the sample subjected to external forces or heat, which β-crystal Type will be transformed into a-crystal type, when the crystal will produce subtle cracks and caves.