Stereocomplex Crystallization between l- and d-Configured Staggered Asymmetric Random Copolymers Based on 2-Hydroxyalkanoic Acids

Abstract

Stereocomplex (SC) crystallization in staggered asymmetric 2-hydroxyalkanoic acid-based random copolymer blends of l-configured poly(l-2-hydroxybutanoic acid-co-l-lactic acid) [P(L-2HB-co-LLA)] (50/50) and d-configured poly(d-2-hydroxybutanoic acid-co-d-2-hydroxy-3-butanoic acid) [P(D-2HB-co-D-2H3MB)] (50/50) composed of monomers with three different chemical structures was reported for the first time. The wide-angle X-ray diffractometry profiles and interplanar distance values of SC crystallites of the staggered asymmetric random copolymer blends were similar to those of poly(l-2-hydroxybutanoic acid)/poly(d-2-hydroxybutanoic acid) SC crystallites. The melting temperature values of SC of copolymer blend samples were much higher than those of P(L-2HB-co-LLA) and P(D-2HB-co-D-2H3MB) individual crystallites of the nonblended P(L-2HB-co-LLA) and P(D-2HB-co-D-2H3MB) samples (90.5 and 96.2–126.0 °C, respectively). Moreover, this article reports for the first time that the 2-hydroxyalkanoic acid-based random co...