【摘要】 使用DSC和偏光显微镜对间规聚丙烯 (sPP)和等规聚丙烯 (iPP)共混物的形态和结晶行为和结晶动力学进行了研究。发现sPP与iPP共混后形成了不相容的多相共混体系 ,两共混组分在各自微区形成结晶。在sPP中混入少量iPP一方面改变了sPP结晶的成核机理和生长方式 ,另一方面对sPP的结晶起到明显的促进作用 ,使sPP的结晶速率常数增大、半结晶时间减少、结晶活化能下降。同时共混还可以提高sPP的结晶度和结晶熔点。更多还原

【Abstract】 The crystallization morphology and behaviors of blends of metallocene catalyzed syndiotactic polypropylene(sPP) and conventional isotactic polypropylene(iPP) were studied by differential scanning calorimetry and polarizing microscope methods. It was observed that sPP and iPP in the blends each formed its own crystallization structure, which gives the evidence of incompatibility of the two components in the blends. The remarkable increase of Avrami index of sPP, after blending with iPP, suggests that the nucleation and growth mechanism in the crystallization process of sPP in the blends have changed. Acting as nuclear agent, the existence of small proportions of iPP in the blends dramatically hastened crystallization of sPP, in both isothermal and nonisothermal processes. The rate constant (K) of crystallization of sPP increased and the half time of crystallization (t1/2),the crystallization activation energy (ΔE) decreased with the increase of iPP amounts. The higher degree of crystallinity of sPP in the blends was also observed.更多还原