Synthesis and crystallization of well-defined biodegradable miktoarm star PEG-PCL-PLLA copolymer

A well-defined miktoarm star copolymer (μ-PEG-PCL-PLLA) was synthesized and the crystallization behavior of the copolymers was investigated. The structure of copolymer was confirmed by 1 H NMR, the molecular weight and molecular weight distribution were studied by GPC . XRD and POM were used to study the crystallization behavior of the miktoarm star copolymers. The XRD spectra showed that the miktoarm star copolymer showed low crystallinity for the joint of terminal, which limited the mobility of polymeric chains. The POM photographs revealed that PCL segments formed spherulites with PLLA crystalline grains as nucleus due to the good compatibility between PCL and PLLA.