Abstract:

The nonisothermal crystallization behavior of PP/PP-g-NH₂/nano-SiO₂ composites was studied by differential scanning calorimetry (DSC).The Caze method was applied to analyzing the nonisothermal crystallization kinetics.The Avrami exponents indicated that the mechanism of nucleation and growth of crystallization changed with the addition of SiO₂ and PP-g-NH2.The Dobreva method was used to investigate the nucleation activity of silica nanoparticles on the polymer matrix.The results showed that silica had little nucleation activity, but the nucleation activity of silica was much improved with the addition of PP-g-NH2.The Friedman method was used to estimate the effective energy barrier for nonisothermal crystallization.The results revealed that nano-SiO₂ decreased the effective energy barrier of PP, and the addition of PP-g-NH2 further decreased that of PP composites.When 3% nano-silica and 5% PP-g-NH₂ were used, the nucleation activity of silica in composites was significantly improved and the effective energy barrier of PP was decreased.