Synthesis And Characterization Of Hyperbranched Polyester

This work is related to the synthesis and characterization of hyperbranched polyesters from the ring opening polymerization of anhydride and multifunctional epoxy compounds. Succinic anhydride (SA) and glycidol were chosen to synthesize hyperbranched polyesters in one-pot manner. Elemental reactions of the polymerization indicated that the two ring opening reactions of carboxyl group with epoxy and hydroxyl group with anhydride proceeded easily under the mild condition of polymerization. It can be seen from the 1HNMR and IR spectra that two hydroxyl groups on the monoester of glycidol showed approximate reactivity toward anhydride. The ratio of reaction rate of the two hydroxyl groups is 1.32 at 80 ℃ whereas 1.60 at 100℃. The side reaction between carboxyl group and hydroxyl group was not detected below 100癈, but had been found with about 10% yield after 3hr at above 110℃. So the polymerization should not be performed at above 110℃.Due to the special structure of hyperbranched polyester, the branching degree (DB) of the hyperbranched polyesters can be calculated based on 1HNMR spectra. Results show that the ratio of SA to glycidol affects DB. Addition manner and polymerization temperature also have influence on DB. Among the resins synthesized, the highest DB reached 0.7 and the lowest one is 0.42. Also due to the structure of hyperbranched polyester, the actual molecular weight cannot be measured successfully. The results were greatly affected by eluent if measured by GPC. But using the same eluent and under the same condition, the GPC results can be used to compare and analyze. It can be concluded that the ratio SA/glycidol affects the molecular weight.Glycidyl methacrylate (GMA) was successfully introduced into the hyperbranched polyesters through the reaction with carboxyl groups. The functionalized polyesters were characterized by 'HNMR and IR spectra. UV curing results show that faster curing rate can be achieved with higher functionalities. Compared with linear polymer, hyperbranched polyester can lower the line shrinkage rate.