Preparation Of Aliphatic Polyesters From Ring-opening Polymerization Catalyzed By Zinc Adipate

Aliphatic polyesters are among the most promising biodegradable polymers. They are biocompatible, enzymatically and chemically degradableand bioresorbable due to a total metabolization of the degradation products. Ring-opening polymerization(ROP) is the major technique to synthesize the Aliphatic polyester with low polydispersity and well controlled molecular weight. Aliphatic polyester prepared by the ROP process are used in a wide range of applications such as sutures, bone fracture fixation devices, controlled drug release, tissue engineering scaffolds, green plastic wrapping materials and disposal containers. But there are still some problems, such as these researchers were not able to synthesize polyesters in a highly alternating copolymerization, high molecular weight copolymers, narrow molecular weight distributions and some toxic organometallic residues in the polymer. Therefore, the development and design of effective and non-toxic catalyst is very necessary. Based on the previous work, zinc complexes were valued by their high activity, low cost, and negligible toxicity. In this work, Preparation of aliphatic polyesters from Ring-opening polymerization catalyzed by Zinc adipate, The work described in this thesis is summarized as the following:First, ring-opening copolymerization of epoxides with cyclic anhydrides catalyzed by zinc adipate(ZnAA) was investigated in detail. The copolymerization is considered to be anionic coordination mechanism. The results showed that ZnAA is an efficient catalyst for the copolymerization of cyclic anhydride and epoxides to produce polyester in high yield of 99%. The structure of epoxides and cyclic anhydrides made an obvious effect on the copolymerization.Second, ring-opening copolymerization of epichlorohydrin with cyclic anhydrides by zinc adipate(ZnAA) was investigated in detail. The copolymerization to obtain a crosslinked copolymer, is free radical mechanism. Therefore, we add the TEMPO in the ring-opening copolymerization of epichlorohydrin with cyclic anhydrides. The results showed that not only obtained linear polyester but also the polyester can modified futher. Moreover, the graft polymer PSA-ECH-g-St and PSAECH-g-MSt have been prepared.Finally, ring-opening polymerization of ?- caprolactone catalyzed by zinc adipate(Zn AA) /PO was investigated in detail. The structure of the polymers was confirmed by the 1H NMR and FT-IR spectra. The reaction conditions of the polymerization was discussed, the results showed that the yield of polymer increase with the increasing of the reaction temperature and time. The optimum reaction conditions: the n(PO)/n(ZnAA) is 5, n(CL)/n(ZnAA) is 70, the temperature was at 80 °C and the reaction time was 20 hours.