Synthesis and thermal properties of poly(methyl methacrylate)-poly(L-lactic acid)-poly(methyl methacrylate) tri-block copolymer

Poly(methyl methacrylate)-poly(L-lactic acid)-poly(methyl methacrylate) tri-block copolymer was prepared using atom transfer radical polymerization (ATRP). The structure and properties of the copolymer were analyzed using infrared spectroscopy, gel permeation chromatography, nuclear magnetic resonance (1H-NMR, 13C-NMR), thermogravimetry, and differential scanning calorimetry. The kinetic plot for the ATRP of methyl methacrylate using poly(L-lactic acid) (PLLA) as the initiator shows that the reaction time increases linearly with ln[M]0/[M]. The results indicate that it is possible to achieve grafted chains with well-defined molecular weights, and block copolymers with narrowed molecular weight distributions. The thermal stability of PLLA is improved by copolymerization. A new wash-extraction method for removing copper from the ATRP has also exhibits satisfactory results. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012