聚丙烯/层状硅酸盐纳米复合材料的剥离机理与网络结构

对本课题组近年来有关聚丙烯/蒙脱土纳米复合材料的研究内容及重要的研究成果进行了综述。熔体插层法是一种制备聚合物基层状硅酸盐纳米复合材料简便而有效的方法，也是所有目前制备方法中最可能实现产业化的方法。这种制备方法的一个显著特点就是涉及剪切场。对蒙脱土在剪切场中的形态发展和剥离机理进行了研究，这将对在实际熔融加工过程中制备剥离型纳米复合材料具有重要的指导意义。纳米级分散的蒙脱土粒子在含量达到一定程度时会形成介观网络结构，大分子链的运动和松弛会受到限制。同时这种介观填料网络还会对宏观性能产生影响。运用动态保压技术，往复剪切场在注塑过程中被施加到复合材料熔体上，这造成了常规注塑样品所不具有的特殊的多层次分散和取向结构。并对这种多层次结构的形成机理进行了讨论。

Mechanism of Shear-induced Exfoliation and Clay Network in Polypropylene/Layered Silicate Nanocomposites

In this review, some valuable results about polypropylene/layered silicate nanocompsites in our group have been briefly depicted. These research subjects involve: 1) mechanism of shear-induced morphological development and exfoliation of layered clay particles during practical molten compounding; 2) effect of mesoscopic clay network on the retarded motion and relaxation of polymer macromolecular chains, and on the macroscopic properties of nanocomposites; 3) unique hierarchical structure of dispersion and orientation in the injection-molded bars obtained via dynamic packing injection molding, which would exert oscillatory shear on the melt of composite during solidification and cooling stage.