Thermooxidative stability of polypropylene/TiO2 and polypropylene/layered silicate nanocomposites

摘要

Thermooxidative stability of polypropylene (PP), PP/TiO2 and PP/Cloisite 10A nanocomposites was studied using non-isothermal DTA measurements. The effect of various concentrations of both nanofillers on the stability of pristine PP was evaluated. Moreover, the influence of additional processing cycles on the stability of all samples was investigated. For the treatment of the experimental results, our method for the evaluation of the induction periods of thermal oxidation using non-Arrhenian temperature functions was employed. Values of the induction periods were taken as a measure of the samples stability. The results obtained clearly demonstrate that both TiO2 and Cloisite 10A nanoparticles accelerate thermooxidative degradation of PP. Stability of nanocomposites decreases drastically in comparison with pristine PP, especially at lower concentrations of both nanofillers. The lifetime of all PP samples decreases with additional processing cycles. The steepest decrease is observed after first and second additional passes through the extruder, and then, the stability remains almost constant up to five passes.