【摘要】 用示差扫描量热仪测定了共聚聚丙烯(PP)/茂金属线形低密度聚乙烯(m-PE-LLD)共混体系的熔融和等温结晶动力学。结果发现,m-PE-LLD 和 PP 主体中 PE 链段之间存在相互作用。用 Avrami 方程对共混体系的等温结晶动力学进行了研究,m-PE-LLD 的加入对 PP 的结晶动力学参数影响不大,说明 m-PE-LLD 的加入没有起到异相成核作用,而是使 PP 的晶体生长更加完整。由于两者的相容性,m-PE-LLD 的加入明显降低了结晶温度下的过冷度,而使整体结晶速率有所下降。用 Friedman 方程计算了体系的结晶活化能,发现 m-PE-LLD 的加入提高了结晶活化能。同时还用 Hoffman-Lauritzen 理论计算了体系成核参数 K_g。更多还原

【Abstract】 The melting and crystallization behaviors and isothermal crystallization kinetics of polypropy- lene(PP)/metallocene-catalyzed linear low-density polyethylene(m-PE-LLD)blends were studied using differential scanning calorimetry(DSC).It showed that PP and m-PE-LLD are partially miscible.The isothermal crystallization kinetics of the blends could be well described with the Avrami equation.The crystallization mechanism of PP was almost not affected by the inclusion of m-PE-LLD.Values of Avra- mi exponent indicated the crystallization nucleation was heterogeneous,the growth of spherulites was nearly three-dimensional.By addition of m-PE-LLD,both crystallization rate and crystallization temper- ature of PP were decreased.The crystallization activation energy was estimated by Friedman equation, it increased in a little by addition of a small amount of m-PE-LLD,but remained no change with further increasing content of m-PE-LLD.The nucleation constant K_g was determined using the Hoffman-Lau- ritzen equation.更多还原