聚丙烯/间同1,2-聚丁二烯共混物的等温结晶动力学

Isothermal Crystallization Kinetics of Polypropylene/Syndiotactic 1,2 - Polybutadiene Blends

利用Avrami方程研究了聚丙烯(PP)及PP/间同1,2-聚丁二烯(s-PB)共混物的等温结晶动力学。DSC研究表明:在相同的结晶温度下,如128℃时共混物的结晶速率为0.45min^(-1),比纯PP的0.17min^(-1)大,s-PB起到了成核剂的作用,使共混物的结晶速率加快;共混物的Avrami指数n为2.71～3.23,共混物的结晶主要是以三维方式增长、异相成核。共混物的Arrhenius结晶活化能为309.35kJ·mol^(-1)比纯PP的338.11kJ·mol^(-1)低,结晶活化能的降低也证明了s-PB在共混物的结晶过程中起到了成核剂的作用并使结晶速率加快。

The isothermal crystallization kinetics of neat PP and PP/s-PB blends was studied using differential scanning calorimetry. The s-PB acted as a heterogeneous nucleation agent and thus accelerated the crystallization rate and decreased the activation energy. At a same crystallization temperature of 128 ℃, the crystallization rate of the blends was 0.45 min^-1 in contrast with 0.17 min^-1 for neat PP. The activation energy was decreased from 338.11 kJ· mol^-1 for neat PP to 309.35 kJ·mol^-1 for the blends. The Avrami exponent n of the blends was in the range of 2.71 to 3.23, which suggested that the isothermal crystallization of the blends followed a three-dimensional growth via heterogeneous nucleation.