| 초록 |
Amorphous glassy materials are thermodynamically unstable and during storage their structures tend to relax toward the equilibrium state. Some macroscopic properties can be affected by the enthalpy relaxation in amorphous glassy materials. Polylactides (PLA) has recently attracted great attention from industry and academia, since it has high potential as packaging film, fiber, and consumer goods due to its excellent transparancy, compostibility, thermal and mechanical properties. Since Tg of PLA is 50~60oC, depending on the D-isomer content, thermal and mechanical properties of PLA are influenced by the relaxation behavior below Tg. In this study, the enthalpy relaxation behavior of PLA with different D-isomer content was investigated as a function of aging temperature and time by using DSC. The enthalpy relaxation of PLA increased appreciably with increasing aging time and temperature, while it decreased with increasing D-isomer content at a constant aging time and temperature |
