Synthesis and Characterization of Copoly(succinic anhydride-ethylene oxide)-Poly(L-lactide) Block Copolymer

The polymerization of L-lactide (LA) was carried out in the presence of tin(II) 2-ethylhexanoate, Sn-(Oct)2and copoly[succinic anhydride (SA)-ethylene oxide (EO)] which has a hydroxyl end group. The synthesized copolymers were characterized by GPC, 1H NMR, 13C NMR, and DSC. The products were block copolymers consisting of copoly(SA-EO) and poly(L-lactide) (PLA) segments. Optical micrographs of the copolymer films confirmed the presence of spherulitic morphology. Spherulite size was enhanced with increase in the LA content in the copolymers. The block copolymers were hydrolyzed with or without lipase and biodegraded by enzymes from microorganisms in activated sludge. Hydrolyzability decreased with increase in LA content in the block copolymers. The solubility of the block copolymers containing LA segment in tetrahydrofuran (THF) was higher than that of copoly(SA-EO).