An w-telechelic poly(lactic acid), PLA, ionomer was synthesized using a chemical recycling process, in which a transesterification reaction was promoted between a commercial PLA and 2-hydroxyethyl methacrylate to produce a PLA capped on one end with a methacrylate group. The methacrylate-terminated PLA was then reacted with itaconic anhydride to produce telechelic PLAs with one carboxylic acid group, which was neutralized with appropriate metal acetates to produce Na-, Li-, K-, Zn-, Ca- and Y-w-telechelic poly(lactic acid) ionomers (M-cPLA). Functionalization of the PLA was confirmed by FT-IR and ¹H-NMR.

This talk will describe the properties and structure of the M-cPLAs. In general, the T_g and T_m increased with molecular weight (which also lowered the ion-concentration) and ionization of the carboxylic acid, and for a fixed molecular weight, the increase was linearly dependent on the ratio of q/a, where q is the cation charge and a is its ionic radius. The thermal-mechanical properties of the ionomers were measured by thermomechanical analysis (TMA). The ionic groups improved resistance to penetration of the TMA probe, and the greatest resistance was achieved with the multivalent cations. The Y-cPLA even displayed a rubber-like plateau in its softening behavior. .