Non-isothermal crystallization kinetics and melting behaviors of nylon 11/tetrapod-shaped ZnO whisker (T-ZnOw) composites

Differential scanning calorimetry (DSC) was used to investigate the non-isothermal crystallization kinetics and melting behaviors of nylon 11/T-ZnOw composites. For non-isothermal studies, the Avrami equation modified by Jeziorny, the Ozawa model and the equation combining the Avrami and Ozawa theories were employed. It was found that the Ozawa model failed to describe the non-isothermal crystallization process for both nylon II and nylon 11/T-ZnOw composites, while the Avrami equation modified by Jeziorny and the equation combining the Avrami and Ozawa theories exhibited great advantages in treating the non-isothermal crystallization kinetics and gave good results. The results showed that the addition of T-ZnOw influenced the mechanism of non-isothermal crystallization and promoted the crystallization rate of PA11 matrix, which indicated that the T-ZnOw might act as a nucleating agent. Further analysis based on the Hoffman-Lauritzen theory was presented. The results revealed that the surface fold free energy sigma(c) and the absolute values of effective activation energy E alpha for PA11/T-ZnOw composites were higher than those for neat PA11, which indicated that the addition of T-ZnOw hindered the mobility of chain segments. Both nylon 11 and nylon 11/ T-ZnOw composites exhibited two melting endotherms, while the equilibrium melting point obtained for PA11/T-ZnOw composites was higher than that for neat PA11. (C) 2007 Elsevier B.V. All rights reserved.