Non-isothermal crystallization kinetics of polypropylene/short glass fibre/multiwalled carbon nanotube composites.

Abstract

The non-isothermal crystallization kinetics of polypropylene (PP) reinforced with multiwalled carbon nanotubes (MWCNTs) and short glass fibres (GF) was studied by differential scanning calorimetry (DSC). The glass fibre concentration was maintained at 20 wt% and the MWCNT content ranged from 1 to 5 wt% in the PP matrix. The crystallization studies performed by DSC showed an increase in crystallization rate and a decrease in half time of crystallization of PP in the presence of micro and nano fillers. The Avrami, Ozawa, and Mo models were applied to analyze the non-isothermal crystallization behavior of PP multiscale composites. The Avrami model could very well describe the crystallization behavior of PP to 70% of the completion of crystallization. Beyond that level, it deviated significantly for all composites. On the other hand, the kinetics of crystallization could be well described by the Mo model. The strongest nucleating effect and the lowest activation energy were obtained for the composite with 2 wt% MWCNT and 20 wt% glass fibre. The X-ray diffraction analysis showed a significant reduction in the average crystal size in accordance with the amount of MWCNTs added.