| 초록 |
A series of well-defined multiarm star block copolymers with fixed total molar mass or having same molar mass per one arm at equivalent block ratio was investigated. We report (a) new methods for preparing (PDL-PLLA)n=2,3,4, or 6 having a PDL inner block and PLLA outer block with an Mn of about 180kgmol-1 (D=1.07-1.14) and fPLLA of 0.27 and disclose (b) the mechanical and thermal properties of the multiarm aliphatic polyester elastomers are enhanced including moduli, toughness, tensile strength, and degradation temperature as increasing n, which was caused by to an amplified pinning effect caused by the more closed packed PLLA domains, in addition to chemical crosslinking of the PDL stands. We also prepared (PDL-PLA)n=1,2,4,6, or 8 multiarm star block copolymers to examine having molar mass of one arm (30kgmol-1) and fPLA of 0.27. Further study is necessary to clarify the effect of molar mass and n on the transition of morphology. |
