Synthesis And Characterization Of Poly Lactic Acid Multiblock Copolymers

A series of multiblock copolymers of PLLA-PEG(PELA) were synthesized by direct melt polycondensation of 1-lactic acid with poly(ethylene glycol) . Poly(l-lactic acid) is the hard block, poly(ethylene glycol) is the soft block of copolymer and adipic acid is a carboxyl/hydroxyl adjusting agent. For the optimization of the reaction conditions, various catalyst systems were examined at different temperature and reaction times. The different quality and molecular weigh of PEG is also considered in this work. The greatest Mw of copolymer is up to 52,000 when SnCl₂· 2H₂O and TSA are used as catalyst in appropriate polymerization. The multiblock structure of copolymers is characterized by IRn NMR and GPC.DSC and DMTA characterize physical performance of copolymer. Glass transition temperature of copolymer is below the room temperature and the copolymer shows the characterization of elastomer. The water absorption and degradation of copolymer are tested in different medium. The result shows that the copolymer has good mechanical performance and hydrophilic characteristic.