Mesoscopic Clay Network In Polypropylene-based Nanocomposites And Its Effects On Macromolecular Relaxation And Orientation Under Shear

In this thesis, the main attention is focused on the relationship of percolated clay network- rheological behavior-molded processing-structural hierarchy-ultimate property in the intercalated polypropylene/organoclay nanocomposites prepared via molten compounding. The retarded motion and relaxation of iPP chains in percolated clay network, the association between morphological development of clay particle and rheological property upon large-amplitude oscillatory shear, the hierarchical structures included dispersion and orientation of layered clay and iPP lamellae in the injection-molded bar, the correlation of rheology-orientation-property and the confined crystallization of iPP chains in the presence of oriented clay layers have been probed profoundly by means of dynamic rheometer, WAXD, TEM, SEM, 2d-WAXS and PLM. Sequentially, some valuable issues will be elucidated as follows, point by point:(1) It was found that the nanodispersed clay tactoids and layers play less important or dominant roles on the mobility of iPP chains depending on the formation of percolating filler network. The essential features of such a mesoscopic...