Study On Bioactive Polymer Materials Design And Properties

Dendrimer-based inorganic-organic binary hybrids have been studied.The structure of the binary hybrid networks exhibit well-known nucleophilicity of their dendrimer domains, which provides for pronounced affinity to complex inorganic, organic, and/or organometallic electrophiles. These unique new materials offer great promise for application in a variety of the challenging areas such assensors, catalytic membranes, medicine and especially, biomaterials.In this paper, We synthesised two kinds of hybrids. Firstly,we utilized the trimethoxysilyi-terminated poly(amidoamine)(PAMAM-OS) dendrimer as a precursor, in which the nucleophilicity of PAMAM domains provides for pronounced affinity to the complex PCL and hydrophobic organosilicon (OS) exteriors of PAMAM-OS form three dimension network structure of cross-linked SiO2, and hybridized with PCL by in situ sol-gel process. The synthesis and characterization of the novel PAMAM-SiO2/PCL ternary hybrid nanocomposites were studied. Secondly, an amphihilic block copolymer (star-PCL-b-PHEMA) based on hyperbranched polyesters (HBP) were prepared and characterized. Their biological activity、biodegradability and biocompatibility were studied.(1) PAMAM were synthesised by divergent method. PAMAM-OS dendrimers derived from hydrophilic polyamidoamine (PAMAM) interiors and hydrophobic trimethoxysilyl (OS) exteriors. PAMAM-SiO2/PCL ternary hybrid nanocomposites with non-covalently and covalently bonding between polymeric and inorganic components were synthesized via in situ sol-gel process of the dendrimer-based precursor (PAMAM-OS). Fourier transform infrared spectroscopy (FTIR) and Solid29Si-NMR spectra results confirmed that the bond linkages between PAMAM-SiO2and PCL components occurred intermolecular hydrogen bonding and covalently bonding in the hybrid system. Thermogravimetric analysis (TGA) results confirmed that the onset and the end point of thermal decomposition temperature of PCL in the hybrid materials are up to380℃and550℃. The microstructure of hybrids was studied by scanning electronic microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC), which showed that the microphase separation in the hybrids occurred at the nano-meter scale. After a PCL is hybridized, the relative degree of crystallinity and the enthalpy of fusion decreased and the corresponding scale of microlite changed.(2)RAFT is a very useful method for Synthetic of amphiphilic block copolymers.A novel star biodegradable amphiphilic block copolymer consisting of poly(ε-caprolactone) and Poly(2-Hydroxyethyl methacrylate) were successfully prepared with good control via reversible addition-fragmentation chain transfer (RAFT), which utilized hyperbranched polyesters as a coinitiator. The composition and structure of the star block copolymer were characterized by1H-NMR,13C-NMR, and FT-IR, and the molecular weight and molecular weight distribution were analyzed by GPC measurements to confirm the diblock structure.The molecular weight of star-PCL and star-PCL11-b-PHEMA17were calculated by1H NMR to be29,856g/mol and68,117g/mol. But the one of star-PCL and star-PCL11-b-PHEMA17were measured by GPC to be29,810g/mol and68050g/mol. The molecular distribution was determined to be1.27and1.17. The distribution coefficient of star-PCL-b-PHEMA was low comparatively. The molecular weight of star-PCL-b-PHEMA measured by GPC was lower than the one measured by1H NMR. The reason was the linear polystyrene was used as standards.(3) This paper explored the potential of star-PCL-PHEMA being used as biomedical material by studying its biocompatibility and biocompatibility in vitro. Cytocompatibility including cytotoxicity of star-PCL-PHEMA film extracts and cell coculture experiments. Osteo-like cells Rosl7/2.8attached and spread much better than on star-PCL, and the cyto toxicity evaluation was acceptable. The results show that star-PCL-PHEMA have great potential as biomedicalmaterials. This paper is mainly aimed at investigation in the surface morphology、pH、molecular weight and weight loss rate of star-PCL-PHEMA and star-PCL in biocompatibility.It was found through the experiments that, the changing rates of the star-PCL were slower than the degree of star-PCL-PHEMA change compared to pH、molecular weight and weight loss rate. This has a guiding significance to the further application of star-PCL-PHEMA.These findings enrich our knowledge of the modification of PCL by copolymerization of PCL with polymer and adding inorganic particles. In the novel PAMAM-SiO2/PCL ternary hybrid nanocomposites, hydrophilic polyamidoamine (PAMAM) interiors and hydrophobic trimethoxysilyl (OS) exteriors improve mechanical strength、melting point of PCL. In amphiphilic biodegradable block copolymer star-PCL-b-PHEMA,the hydrophobic block PCL and the hydrophilic block PHEMA are biocompatible and biodegradable. Therefore, star-PCL-b-PHEMA as drug carrier in the future is based on the study about biocompatible and biodegradable. It is significant on the phannaceutical application.