Abstract: The nonisothermal crystallization kinetics of PP/nano-SiO2 composites was studied uisng differential scanning calorimetry (DSC), the nucleation activity of silica nanoparticles in the polymer matrix and the effective energy barrier for nonisothermal crystallization were explored. Results showed that the nano-SiO2 had a heterogeneous nucleation effect on the polymer matrix, increasing the peak crystallization temperature and the overall rate of crystallization of PP. PP-g-MAH enhanced the nucleation activity of the silica nanoparticles in the PP matrix. Nano-SiO2 decreased the effective energy barrier of PP, the addition of PP-g-MAH in PP/SiO2 increased the effective energy barrier of the composites, but lower than that of neat PP.

Key words: polypropylene, nano-silica, crystallization kinetics, nucleation activity, effective energy barrier