The influence of suflace grafting nlodified nano-silica on the isothermal and non-isothermal crystallization kinetics of isotaetic polypropylene (IPP) was investigated by DSC The silica panicles 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 lnehing point

as well as higher crystallinity and the overall rate of crystallization

but lower crystalline regularity．The surface grafting treatment of the nanopartieles 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-siliea．The later has a more uniform crystal structure because the fillers act as nucleates．However

a faster isothermal crystallization process of the PP filled with nano-silica results in a lower equilibrium melting point．implying that the crystalline structure is less perfect in this ease．