Temperature dependence of the molecular motion in the crystalline region of biodegradable poly(butylene adipate), poly(ethylene succinate), and poly(butylene succinate)

The information on molecular dynamics in solid-state polymers is of importance for controlling mechanical strength, processibility, and biodegradability. In our former article, molecular motion in the crystalline region of poly(butylene succinate) (PBS) and poly(butylene succinate-co-20 mol% butylene adipate) [P(BS-co-20 mol% BA)] at room temperature have been analyzed by C-13 spin-lattice relaxation behavior (T-1C relaxation behavior). In the present study, at first, molecular motion at room temperature in the crystalline region of poly(butylene adipate) (PBA) and poly(ethylene succinate) (PES) have been investigated by the same T-1C method. As the result, it has been found that both the PBA and PES samples include two crystalline components with different molecular mobility. The rigid crystalline component is assignable to inner crystalline region (core of crystalline region) and the relatively mobile crystalline component is ascribed to interfacial crystalline region (crystalline region near amorphous area). To investigate the temperature dependence of molecular mobility, variable temperature T-1C measurements have been carried out for PBA, PES, and PBS samples. With increasing the temperature, remarkable change in molecular mobility has been seen in PBS sample. PES sample has also showed the increase in molecular mobility but the amount of the change has been smaller than that of PBS In PBA. the molecular mobility reflected in T-1C is almost independent of temperature. The significant molecular motion peculiar in PBS has been discussed. (C) 2004 Elsevier Ltd. All rights reserved.