Small-angle X-ray scattering (SAXS), optical microscopy and differenti
al scanning calorimetry were used to establish relationships between c
rystallization, microstructure, and equilibrium melting temperature (T
-m(0)) for random copolymers of poly(L-lactide-co-meso-lactide). T(m)(
0)s derived using the Gibbs-Thomson and data-fitting(23) approaches we
re found to be in excellent agreement and decreased significantly with
increasing meso-lactide concentration. Analysis of these equilibrium
melting temperatures using models for copolymer crystallization leads
to the conclusion that the meso defects are rejected from the crystall
ine regions. From analysis of the SAXS data, it was concluded that the
copolymers contained significant interfibrillar regions whose concent
ration increased with higher comonomer content. Spherulitic growth rat
es were strongly dependent on meso content and were analyzed using the
Lauritzen-Hoffman kinetic theory of crystal growth.