国外抗冲共聚聚丙烯结构的研究

Characterization of impact propylene-ethylene copolymer

利用升温淋洗分级柱、核磁共振波谱仪、差示扫描量热仪、凝胶渗透色谱仪和扫描电子显微镜等研究了国外抗冲共聚聚丙烯(PP)的组成、序列结构、相对分子质量及其分布、热转变、相态结构和宏观性能。结果表明,该抗冲共聚PP由均聚PP、乙丙橡胶和可结晶的乙丙共聚物组成,具有优良的机械性能;均聚PP为抗冲共聚物提供刚性,乙丙橡胶可提高抗冲共聚物的韧性;抗冲共聚物的相对分子质量呈多分散性,其分布较宽;乙丙橡胶的相对分子质量较大,以直径为1～2μm的微粒均匀分布在PP基体中,有利于提高抗冲共聚物的冲击强度;抗冲共聚物的熔点较高,耐热性好。

This paper studied composition, sequential structure, relative molecular mass and its distribution, heat transition, phase structure and macroscopic properties of overseas impact ethylene-propylene copolymers by means of temperature rising elution fractionation （TREF）, nuclear magnetic resonance spectrometer, differential scanning calorimeter, gel permeation chromatograph and scanning electron microscope. The results confirm that the impact copolymer consists of homopolypropylene, ethylene-propylene rubber （EPR） and crystallizable ethylene-propylene copolymer, featuring superior mechanical properties. The homopolypropylene and EPR endue the impact eopolymer with stiffness and toughness, respectively. The relative molecular mass of the impact copolymer possesses polydispersity and wider distribution. EPR has higher relative molecular mass and exists in the shape of particulate with diameter of 1-2 micrometer homogeneously dispersed in the polypropylene matrix, and thereby benefiting rise in impact strength of the impact copolymer. In addition, the impact copolymer also has higher melting point and heat resistance.