| 초록 |
Poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) like other chiral polymers can form a racemate, and the physical properties of which are different from those of the individual enantiomers. It is well-known that D- and L-forms of low molecular weight compounds can produce racemic crystals upon mixing if their molecular affinity is sufficiently strong. In the present study, D- and L-lactides, which are the cyclic monomers of PDLA and PLLA, respectively, possess a melting point at around 170 oC. In contrast, their racemic compound melts at around 225 oC, a higher temperature than the melting point of PDLA and PLLA. DSC is one of the first choice methods to confirm stereocomplex formation. In most cases stereocomplexes show a characteristic increase in melting temperature. Besides, IR and XRD are employed to investigate blend of stereocomplexation and change of crystallinity. |
