Synthesis of starch-g-lactic acid copolymer with high grafting degree catalyzed by ammonia water

The study of starch-g-lactic acid copolymer has gained much attention for its completely degradable property, but its intricate synthetic procedure and low graft degree inhibited its further application. In this work, the synthesis of starch-g-lactic acid copolymer was attempted via the catalysis of ammonia water by one-step process, and the structure of starch-g-lactic acid copolymer was characterized by means of IR, C-13 NMR and HMBC. The synthetic conditions were optimized as follows, the starch was activated for 2 h at 80 degrees C at first, starch and lactic acid with weight ratios of 1:4 reacted for 4h at 90 degrees C in vacuum. The starch-g-lactic acid copolymer can be finally obtained with graft degree of starch 58.9%. (C) 2014 Elsevier Ltd. All rights reserved.