Study On Synthesis And Properties Of Ion-functionalized Polyester

Aliphatic polyester has become one of the most important biomaterials due to the unique characteristics of biodegradability and biocompatibility and low cost.However,the major drawbacks of lacking hydrophilicity and readily available reactive groups hinder their wide use in biomedical and pharmaceutical fields.Functional modification of aliphatic polyesters to achieve control of their performance to meet the needs of practical applications has great significance.Poly(butylene succinate-co-butylene fumarate)(PBSF)is a novel unsaturated aliphatic polyester,which can be degraded into non-toxic oligomer and monomer by microorganisms or enzymes and it has good biocompatibility and biodegradability.This paper will develop a novel cationic biodegradable polyester materials and study of their structure and properties through functional modification.In addition,PES is a homologue of PBS.PES is a kind of environmentally friendly polyester with promising prospects because of its abundant raw materials,good performance,biodegradability and low cost.At present,PES synthesized by process are mostly low molecular weight and poor performance,so its performance can improve of low molecular weight PES by zwitterionic functional modification.1.In this study,a series of random copolyesters of poly(butylene succinate-co-butylene fumarate)(PBSF)with different content of carbon-carbon double bonds were synthesized via esterification and copolycondensation of fumaric acid,succinic acid and 1,4-butanediol.Then brominated poly(butylene succinate)(BPBS)was prepared by addition of bromine to carbon-carbon double bonds on the backbone of PBSF.Finally,the quaternization of BPBS with series of N,N-dimethyl alkylamines afforded poly(butylene succinate)containing quaternary ammonium cations(QPBS)with various ion contents and alkyl chain lengths.The chemical structures of unsaturated copolyesters and novel cationic polyesters were systematically characterized by ~1H-NMR,ATR-FTIR and GPC.The bulk and surface nitrogen ion contents of unsaturated polyesters and cationically functionalized polyesters were analyzed and compared using X-ray photoelectron spectroscopy(XPS)and elemental analysis.The hydrophilicity,antibacterial activity and cytotoxicity of the copolyester were studied by water contact angle(WCA),inhibition zone method,OD600 method,scanning electron microscope(SEM)and CCK-8 method.WCA experiments show that the hydrophilicity of cationic copolyester has greatly improved after the introduction of the quaternary ammonium salt cation in the bone chain.The antibacterial study reveals that cationic copolyesters exhibited excellent antibacterial performance for both S.aureus and E.coli when the alkyl chain length was greater than 8,as compared with the ion content and alkyl chain length is a more important factor for the antibacterial performance.Cytotoxicity assay suggested that the cationic polyesters have good cytotoxicity.Considering the biodegradation,good antibacterial activities and simple process,this kind of material may have great potential to be applied as biomaterials.2.Low molecular weight poly(ethylene succinate)(PES)were synthesized via esterification and polycondensation of succinic acid and ethylene glycol.Phosphorylcholine(PC)end-capped poly(butylene succinate)(PES-PC)were synthesized by reacting 2-chloroethyl dichlorophosphoric acid with terminal group,followed by phosphorylation and quaternization to introduce PC group on the terminal group.The chemical structures of Low molecular weight polyesters and novel zwitterionic polyesters were systematically characterized by ~1H-NMR and ATR-FTIR.The bulk and surface elemental contents of unsaturated polyesters and cationically functionalized polyesters were analyzed and compared using X-ray photoelectron and spectroscopy(XPS).The hydrophilicity of zwitterionic copolyester were studied by water static contact angle(WCA).WCA experiments show that the hydrophilicity of zwitterionic copolyester has greatly improved after the introduction of the PC group in the terminal.