Study On Polytrimethylene Carbonate And Its Derivatives

At present,functional degradable polymer materials have great application in medical field.Aliphatic polycarbonates possess good biocompatibility,biodegradability,low toxicity,adjustable mechanical properties,and do not produce strong acidic compounds after degradation.Thus they have been widely used in tissue engineering and drug controlled release systems.Poly(trimethylene carbonate)(PTMC)is a biodegradable aliphatic polycarbonate material with low Tg,good biocompatibility,biodegradability,flexibility and elasticity.However,due to its poor mechanical performance,its application in plastic fixation,tissue engineering and other medical fields is greatly limited.Therefore,in order to improve the physical and mechanical properties of PTMC,the design and synthesis of biodegradable polymers based on trimethylene carbonate(TMC)has become a hot research topic.In this thesis,physical and chemical modification of PTMC was studied and PTMC/hydroxyapatite composite,star PTMC,lactide(LA)and trimethylene carbonate copolymer were also prepared.The main contents of this thesis are as follows:1.Poly(trimethylene carbonate)/hydroxyapatite composites(PTMC/HA)Trimethylene carbonate(TMC)was firstly synthesized from 1,3-propanediol and ethyl chloroformate as the raw materials.Poly(trimethylene carbonate)(PTMC)was further synthesized by ring-opening polymerization of TMC using stannous octanoate as a catalyst.Subsequently,poly(trimethylene carbonate)/hydroxyapatite composites(PTMC/HA)were prepared by the blending with PTMC and nano-hydroxyapatite(HA).Their structures of the materials were also characterized.The Fourier transform infrared spectroscopy(FT-IR),thermal stability,melting behavior,hydrophobicity and mechanical properties of PTMC and PTMC/HA were compared.The experimental results show that PTMC/HA composites have higher tensile strength and flexural strength than PTMC.2.Star poly(trimethylene carbonate)(PTMC)Four-arm and six-arm star poly(trimethylene carbonate)s were synthesized by ring-opening polymerization of pentaerythritol and inositol with TMC as a monomer and stannous octanoate as a catalyst,respectively.Their structures of the materials were also characterized by ~1H NMR,FT-IR and gel permeation chromatography(GPC).3.Poly(trimethylene carbonate-co-lactide)(P(TMC-co-LA))Poly(trimethylene carbonate-co-lactide)copolymers(P(TMC-co-LA))were synthesized by ring-opening copolymerization of TMC and lactide(LA)using stannous octanoate as a catalyst.Their structures of P(TMC-co-LA)were also characterized by~1H NMR,FT-IR and gel permeation chromatography(GPC).The optimum conditions for copolymerization of TMC and LA were also optimized.