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

• We prepared poly(d,l-lactide)/stereocomplex of poly(l- and d-lactide) blends.
• The miscibility of the polymer blends was assessed.
• The addition of PDLLA to sc-PLA restrains the overall crystallization process.
• The combined Ozawa–Avrami model described nonisothermal crystallization behavior.
• The activation energy of samples based on Friedman equation was evaluated.

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.