Effects of molten poly(d,l-lactide) on nonisothermal crystallization in stereocomplex of poly(l-lactide) with poly(d-lactide)

摘要

Poly(d,l-lactide) (PDLLA) and stereocomplex-poly (l- and d-lactide) (sc-PLA) blends were prepared by solution blending. The influence of the addition of PDLLA on nonisothermal crystallization behavior of sc-PLA was investigated. It was observed that the crystallization peak temperature of PDLLA/sc-PLA blends was marginally lower than that of neat sc-PLA at various cooling rates. Furthermore, the half-time for crystallization increased with an increase in PDLLA content, indicating the dilution effect of PDLLA on the sc-PLA component to restraint the overall crystallization process. The nonisothermal crystallization data was analyzed using Avrami, Ozawa and combined Ozawa-Avrami models methods. The validity of kinetic models on the nonisothermal crystallization process of neat sc-PLA and PDLLA/sc-PLA blends was discussed. The approach developed by combined Ozawa-Avrami models successfully described the nonisothermal crystallization behavior of neat sc-PLA and PDLLA/sc-PLA blends. The activation energy for nonisothermal crystallization of neat sc-PLA and PDLLA/sc-PLA blends based on Friedman equation was evaluated.