Functional Polycarbonate: Enzymatic Synthesis And Modification To Polylactide

Biodegradable polymer is one of the most important biomedical materials. They have attracted much of attention and rapid development because they eliminate the need for surgical removal after implantation. Polyesters and Polycarbonates are known to be biocompatibility and biodegradability polymers, which have been widely studied for biomedical applications, such as suture, bone fixation materials and drug controlled-release carriers. In this paper, the development of synthesis and modification of polyesters and polycarbonates is reviewed.In the biomedical fields, biodegradable and bioresorbable polymers having pendent functional groups are of particular importance. Functional groups can be used to regulate the properties of the polymers. In addition, they also provide an opportunity for attaching drugs or bioactive components to make these polymers suitable for use in a variety of medical application. However, polymers with pendent functional groups were generally prepared through protecting-deprotecting process, which was not only fussy but also difficult to control the efficiency of the deprotecting. Recently, enzymatic polymerization has been known as new methodology of polymer syntheses, which has been applied to synthesize polymers that are difficult to be prepared by traditional method. In this paper, porcine pancreas lipase immobilized on silica particles were prepared and employed successfully for ring-opening polymerization of 5-methyl-5-carbonyl-1,3-dioxan-2-one(MCC) for the first time. The structure of polymer was confirmed by 1H NMR and IR.Copolymerization is one kind of convenient method to synthesis polymer materials with different properties by altering the kinds of comonomers or the ratios of the comonomers. In this paper, one-step synthesis of poly(ester-carbonates) containing pendant carboxyl groups (poly(DLLA-co-MCC)) was successfully performed using immobilized lipase on porous silica beads as catalysts. The copolymers werecharacterized by IR, 1H NMR and Ubbelohde Viscometer. The factors affecting the viscosity of the copolymer and yield such as reaction temperature, reaction time, enzyme concentration and the ratio of the two monomers were investigated.Blend is another kind of useful method to synthesis polymer materials with good properties. In this paper, polylactide was blended with PMCC at the ratio from 0% to 30 wt.- %. The properties of resulting blends were studied. Increasing the content of PMCC resulted in the increase of hydrophilicity, hydrolytic degradation and drug release rate.