Photopolymerization of biocompatible films containing poly(lactic acid)

Telechelic acrylic poly(lactic acid) (PLA) oligomers were synthesized from the transesterification of PLA with ethylene glycol diacrylate. The oligoesters were characterized by 1H NMR and GPC. The telechelic acrylic PLA oligomers were then formulated with four different reactive diluents and photopolymerized into films with photoinitiator Irgacure 2959. Films were formulated to contain either 1,4-butanediol dimethacrylate (BDDM) or triethylene glycol dimethacrylate (TEGDMA) and for each set of formulations the concentration of PLA was varied from 0 to 70 wt.%. The kinetics of the photopolymerizable material was studied by photo-differential scanning calorimeter (DSC). Physical properties were evaluated using pencil hardness, reverse impact resistance, pull off adhesion, solvent resistance, and dynamic mechanical thermal analysis (DMTA) properties. The Photo-DSC results showed that the reaction rate decreased as the PLA concentration increased. Films containing lower concentrations of PLA were harder and less flexible.