| 초록 |
Polylactides (PLA) has recently received much attention from industry and academia because it has an excellent transparency, compostibility, thermal and mechanical properties as an eco-friendly packaging film or fiber material. Since orientation process is essential for film and fiber applications of PLA, understanding the effects of chain orientation on the enthalpy relaxation and glass transition of PLA is needed to be pursued. Therefore, in this study, a series of amorphous PLA films oriented uniaxially at different draw ratio were prepared by using UTM equipped with temperature-controlled chamber. The chain orientation, glass transition, and thermomechanical properties of the oriented films were investigated by WAXD, DSC, DMA, respectively. Interestingly, it was found that the oriented films exhibit higher glass transition temperatures and increased enthalpy relaxation endothermic peaks with the increment of the draw ratio, which was analyzed on the basis of thermodynamic model. |
