Abstract: Thermogravimetric analysis was used to study the polypropylene(PP) and polypropylene/montmorillonite (PP/OMMT) composites. the thermal decomposition kinetics parameters of PP and PP/OMMT composites (4 wt% montmorillonite) was calculated by means of Qzawa method at different heating rates of 10，20，30 and 40 K/min in nitrogen atmosphere，thermal decomposition kinetics mechanism was studied by Coats-Redfern method. thermal decomposition of both PP and PP/OMMT composite were completed in one step. the activation energy of PP was lower than that of composites before 22 wt% mass loss, and higher after 22 wt% mass loss. the most probable kinetic function of the thermal decomposition of PP and PP/OMMT composites was the Valensi function with n=1/2 and Mampel Power theorem with n=1 /4.

Key words: polypropylene, montmorillonite, thermal decomposition, kinetics