Synthesis of poly(lactic acid-co-menthol) via direct melt polycondensation and its characterization

Directly starting from D,L-lactic acid (LA) and L-menthol, poly(lactic acid-co-menthol) (PLAM) as potential solid mint flavor was synthesized via melt polycondensation. The synthetic conditions, including type and dosage of catalyst, temperature and time of copolymerization, were discussed. The structure and properties of the copolymer were systematically characterized with FTIR, 1H-NMR, GPC, DSC, TG, and XRD. The influences of molar feed ratios on the properties of PLAM were also discussed. The copolymer PLAM with the biggest Mw of 11,600 Da was obtained. The Tg of PLAM is lower than the Tg of homopolymer poly(D,L-lactic acid) (PDLLA), and all copolymers have higher thermal decomposition temperature. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012