LAUSR

A high-molecular-weight polyester of poly(mandelate-co-lactate) (PML) is prepared by ring-opening polymerization of stereo-configuration controlled cyclic diester monomers of methyl-6-phenyl-1,4-dioxane-2,5-dione (MPDD) and lactide. The attained PML shows excellent glassy properties, although the original stereo-configuration of MPDD is not preserved. The intrinsic high glass transition temperature (T-g) of PML is promising, and it is able to be further enhanced by thermal treatment to as high as 90 degrees C. Interestingly, the enhanced high T-g is attained by only 15 mol% of mandelate content in the polymer chain which is far lower than the ones suggested by theoretical calculation. The enhancement in T-g is also attained by polymer blending of PML and poly(l-lactide) (PLLA). The T-g of the polymer blend also reaches 90 degrees C which is almost 20 degrees C higher than the ones suggested by theoretical calculations. These results indicate that the rigid mandelate unit consisting of phenyl groups in PML chain effectively interact with PLLA chains in amorphous domain to restrict their chain mobility. The thermal and glassy properties are sufficient to explore new applications in engineering fields.