Synthesis And Characterization On Medical Biodegradable Polyesters

A new method for the synthesis of biodegradable multifunctional group-terminated copolymers is introduced, by which a series of novel biodegradable polyesters copolymers such as PCLA and PLGA are synthesized for the first time. The structure and thermal property of the copolymer were characterized by FTIR,1H-NMR, and DSC.The results showed that the relatively high yield of PCLA-OH can be acquired under the conditions of the monomer (glycolide and caprolactone) ratio of 3:7 and adding 5wt% catalyst (stannous octanoate) based on the monomer amout,5% of co-initiator (1, 4-butanediol)to monomer, polymerization at 150℃ and after 3h. In addition, by changing the total amount of 1,4-butanediol, PCLA-OH with different molecular weight can be prepared. The optimal solution of preparing PCLA-Boc is under the conditions of the raw material (PCLA-OH and Di-Boc lysine) ratio of 1:3, adding an equal molar amount of catalyst (DPTS), which compared with the amount of PCLA-OH used, and an equal molar amount of coupling agent (DIPC), which compared with the amount of Di-Boc lysine used, left at room temperature for 24h. The best mothed of preparing PCLA-NH2 is under the conditions of, for every 1g of polymer used,3ml of trifluoroacetic is added at 0℃ for 4h. The structure of the copolymers were characterized by FTIR and 1H-NMR, the results demonstrated that the products obtained were PLGA-OH, PLGA-Boc and PLGA-NH2. PCLA are charactered by DSC, the results show that Tg of the copolymer increases with the increase of molecular weight, Tg of PCLA-NH2 is lower than that of PCLA-Boc, which higher than that of PCLA-OH. In addition, we also synthesised different molecular weight of PLGA-OH, PLGA-Boc and PLGA-NH2 under the conditions of the different total amount of 1,4-butanediol. The copolymers were characterized by FTIR, and 1H-NMR, the results demonstrated that the structure of copolymer were similar to the theory. Copolymers were charactered by DSC, the results showed that Tg of PLGA-OH is lowest, Tg of PLGA-Boc is highest, and Tg of PLGA-NH2 is between them. And the results showed that molecular weight of PLGA-NH2 decreases with the increase of total amount of 1,4-butanediol, and Tg of PLGA-NH2 showed the tendency of decreasing.In the present paper, we prepared a series of biodegradable multifunctional polyester macromonomer. This versatile synthetic platform can provide a large family of biodegradable, tetra-amino-terminated telechelic copolymers with better properties useful for the preparation of network biodegradable polyester elastomer with tailorable properties.