Study On Lipase-Catalyzed Synthesis Of Completety Degradable Grafted Copolymer Based On Starch In Non-aqueous

The preparation of starch/ε-Caprolactone grafted copolymer and starch/ L-lactide grafted copolymer by using lipase as catalyst in non-aqueous system was investigated. The structure of these copolymers was characterized with FTIR, NMR, DSC and XRD. The effect of temperature, initial water activity, pH, and the ratio of CL to starch on the grafted copolymerization was studied.Starch/ε-Caprolactone grafted copolymer was synthesized by using porcine pancreatic lipase as catalyze in DMSO solution. The structure of the copolymer was characterized by FTIR and NMR. The results indicated that PCL was grafted on the starch and more than 97 percent PCL was grafted at the hydroxys of C2,C3 of starch. The effect of temperature, initial water activity, pH, and the ratio of CL to starch on the grafted copolymerization was investigated. The results indicated that the optimum synthesis conditions were as follows: temperature 50℃, initial water activity 0.75, pH7.5, the molar of CL to starch is above 6. The thermal properties, dissolution properties and degradation properties of copolymer was studied.Starch/L-lactide grafted copolymer was synthesized by using Novozyme435 as catalyze in DMSO solution. The structure of the copolymer was characterized by FTIR and NMR. Research the effect of molar ratio of the substrates (St/LA) on grafting rate and copolymers'thermal properties, dissolution properties and degradation in acid-base solution.Starch/L-lactide grafted copolymer with different sources of starch was prepared by using Novozyme435 as a catalyst. The structure of the copolymer was characterized by FTIR and NMR. The relationship between the sources, composition, internal structure of starch and the properties of grafted copolymer was discussed.