聚丙烯/硫酸钡复合体系的界面相互作用与流变性质和结晶行为的关系

EFFECT OF INTERFACIAL INTERACTION ON RHEOLOGICAL AND CRYSTALLINE BEHAVIOR OF POLYPROPYLENE/BaSO_4 COMPOSITES

制备了一系列具有不同界面状态的聚丙烯 (PP) 硫酸钡 (BaSO4)复合体 .PP BaSO4的界面分别用硅烷、硬脂酸、马来酸酐接枝聚丙烯 (PP g MAH)改性 .研究表明 ,填充体系的熔体粘度和熔体弹性均高于基体 .以硅烷和PP g MAH进行界面改性后 ,PP BaSO4的界面相互作用加强 ,导致复合体系中的熔体粘度和熔体弹性进一步提高 ,同时BaSO4对PP的成核活性提高 .填料用硬脂酸处理后 ,硬脂酸能够在填料粒子表面上形成一个包覆层 ,使粒子与PP的亲和性改善 .同时该包覆层具有润滑作用 ,使得复合体系的熔体粘度和熔体弹性下降 ,并使得该体系中BaSO4的成核活性低于硅烷和处理的体系 .本文探讨了由复合体系的熔体粘度定量比较填充复合体系中聚合物 填料界面相互作用的方法 。

A group of polypropylene ( PP)/barium sulfate ( BaSO4) composites with different polymer-filler interfacial interaction were prepared by treating the fillers with coupling agents or incorporating functionalized PP (PP-g-MAH). The effect of interfacial modification on the rheological and crystalline behavior of the composites was investigated. It is shown that the interfacial adhesion between the filler and matrix was increased when the fillers were treated with silane or the PP-g-MAH was added into the composites. Under such circumstances, the mobility of the PP chains decreased, leading to high shear viscosity, shear stress and melt elasticity. On the other hand, the improved polymer-filler compatibility contributed to the increase of the heterogeneous nucleating activity of the filler on the PP.A model of 'effective occupied volume' was employed to illustrate the effect interfacial interaction and a parameter was introduced to evaluate the interfacial interaction quantitatively.