Effect of Organic Modification of SiO2 on Non-isothermal Crystallization of PET in PET/SiO2 Nanocomposites

Nanocomposites of PET/SiO2 (unmodified and modified by organic agents) were prepared by melt blending, to study the effect of organic modification of SiO2 on their morphology and crystallization behaviour. The crystallization behaviours of PET/SiO2 nanocomposites were investigated by differential scanning calorimetry (DSC), and the non-isothermal crystallization kinetics were analyzed by Jeziorny and Ozawa equations. The DSC cooling scanning curves showed that the crystallization peak became very narrow and Tmc shifted largely to high temperature region in presence of SiO2 which totally behaved as nucleating agent for PET. By Jeziorny equation it is shown that all the three different surface characteristics of SiO2 accelerated the crystallization rate and the values of the Avrami exponents (n) of PET/SiO2 nanocomposites remanined virtually unchanged as compared to those of the virgin PET. Ozawa equation, however, failed to reveal the non-isothermal crystallization kinetics of PET/SiO2 nanocomposites.