Miscibility and crystallization behaviors of stereocomplex-type poly(l- and d-lactide)/poly(methyl methacrylate) blends

Abstract

Stereocomplex-poly(l- and d-lactide) (sc-PLA) and poly(methyl methacrylate) (PMMA) blends were prepared by solution blending at PMMA loadings from 20 to 80 mass%. The miscibility and crystallization behaviors of the blends have been studied in detail by differential scanning calorimeter. The single-glass transition temperatures (T g) of the blends demonstrated that the obtained system was miscible in the amorphous state. It was observed that the crystallization peak temperature of sc-PLA/PMMA blends was marginally lower than that of neat sc-PLA at various cooling rates, indicating the dilution effect of PMMA on the sc-PLA component to restrain the overall crystallization process. In the study of isothermal crystallization kinetics, the reciprocal value of crystallization peak time ( $$ t_{\text{p}}^{ - 1} $$ ) decreased with increasing PMMA content, indicating that the addition of non-crystalline PMMA inhibited the isothermal crystallization of sc-PLA at an identical crystallization temperature (T c). Moreover, the negative value of Flory–Huggins interaction parameter (χ 12 = −0.16) of the blend further indicated that sc-PLA and PMMA formed miscible blends.