Separate crystallization and cocrystallization of poly(L-lactide) in the presence of L-lactide-based copolymers with low crystallizability, poly(L-lactide-co-glycolide) and poly(L-lactide-co-D-lactide)

Abstract

Poly(L-lactide) (PLLA) and poly(L-lactide-co-glycolide) (78/22)0 [P(LLA-GA)] were phase-separated in PLLA/P(LLA-GA) blends, forming independent domains and thence crystallizing separately. The crystallization of PLLA was not disturbed or delayed by the presence of P(LLA-GA) and vice versa. PLLA and poly(L-lactide-co-D-lactide) (77/23) [P(LLA-DLA)] were miscible in the PLLA/P(LLA-DLA) blends, overall crystallization was delayed, and the growth of crystallites was disturbed in the presence of P(LLA-DLA). In isothermal crystallization, the originally noncrystallizable P(LLA-DLA) became crystallizable in the presence of PLLA, with which it cocrystallized. The disturbance effect on periodical lamella twisting of PLLA was larger for P(LLA-GA) than for P(LLA-DLA). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.