Abstract
The influence of surface grafting modified nano-silica on the isothermal and non-isothermal crystallization kinetics of isotactic polypropylene (IPP) was investigated by DSC. The silica particles were pre-grafted with styrene, methyl methacrylate, ethyl acrylate and butyl acrylate, respectively. The experimental results show that the addition of nano-silica into PP has an obvious nucleating effect on the crystallization of PP, resulting in higher crystallization temperature and melting point, as well as higher crystallinity and the overall rate of crystallization, but lower crystalline regularity. The surface grafting treatment of the nanoparticles promotes the nucleating effect due to the increased miscibility between the particle and the matrix. The nucleating effect of the particles is also related with their dispersion state in the polymer matrix. The melting behavior of neat PP is different to that of the PP filled with nano-silica. The later has a more uniform crystal structure because the fillers act a