Influence of microstructure on the crystallization of segmented copolymers constituted by glycolide and trimethylene carbonate units

Hot and cold non-isothermal crystallization of copolymers having glycolide hard segments and glycolide-cotrimethylene carbonate soft segments was investigated by calorimetry, optical microscopy and synchrotron radiation experiments. The effect of composition and microstructural changes on thermal properties and morphology of crystallized samples was analyzed. Significant differences were found between the nucleation density of spherulites developed during cold crystallization. Crystallizations from the melt were characterized by a lamellar insertion mechanism and a broad distribution of crystal layer widths. By contrast, cold crystallized samples gave rise to practically constant long periods and narrower distributions. Soft segments with high glycolide content were more easily incorporated in the crystalline phase by decreasing the hard segment content of the sample. A significant decrease on the melting point was observed as well as a decrease of the amorphous layer thickness and an increase of the crystalline lamellar thickness when the sample was hot and cold crystallized, respectively.