| 초록 |
To improve the melting point and crystallization rate of poly(lactic acid)(PLA), its stereocomplex was prepared by melt blending PLLA and PDLA with twin screw extruder. Blend compositions of PLLA/PDLA were 100/0, 25/75, 50/50, 75/25 and 0/100, respectively. Thermal properties, mechanical properties and crystallization behavior were characterized by DSC, DMA, UTM, Izod impact tester. XRD and Polarized microscope. As we expect, Tm of stereocomplexes dramatically increased about 50℃ compared with Tm of each homopolymer. DMA data show that storage modulus of room temperature with increasing PDLA content decreased and impact strength also decreased. Crystallites of stereocomplex were more easily formed and spherulite growth rate increased significantly, too. Also, we tried to improve toughness of PLA by blending with surveyed impact modifier. EGMA was used to strengthen impact strength. We could find well balanced properties of impact strength and flexural modulus at some compositions. |
