Surface Modification Of Nano-hydroxyapatite And Its PLLA Nano-fiber:Synthesis And Characterization

With the rapid development of Chemistry, Materials Science, Medicine and Biology, there has been a huge reformation happened to bone repair materials. From metal alloys, bioinert ceramic material to today's bioactive ceramic material, Nowadays, about using of bioactive material for the substrate to build bone tissue engineering scaffolds and develop into human bone tissue after tissue culture, thus realizes the replacement of a variety of implant materials. It will greatly reduce the pain of patient, lower medical costs and reduce the surgery complication. In recent years, Hydroxyapatite(HA) is the best-studied bioactive ceramic material, It is the major inorganic compound in mammalian hard tissues and has osteoinduction and osteoconduction. However, the pure HA bioceramic is only suitable for the nonload-bearing applications because of its fragility, low mechanical strength. By means of preparation of polymer-based composite materials is an effective way to overcome HA shortcomings. However, the phase compatibility between HA and polymers are poor, HA nanoparticles could aggregate easily in the polymer matrix, limiting the improvement of their mechanical properties. This paper puts forward the chemic grafting modification strategy on the surface of the Hydroxyapatite to increase the interfacial compatibility between hydroxyapatite and polymer matrix. In addition, the fabrication of the nano-fiber by blending the surface modification HA with poly(lactic acid)(PLLA) by using the electrostatic spinning method. The paper has primarily researched the Mechanical properties, Hydrophilic properties and Morphology of the Nano fiber composite materials.Chapter2, In the process of the preparation of HA by hydrothermal technique, the propiolic acid was added and Alkynyl functionalized HA(AHA) were obtained. Then AHA was used to react with azide modified chitosan(CS) to gain CS grafted HA(HA-CS). The synthesis product was determinated by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). As shown in the thermal gravimetric analysis (TGA), the surface grafting amounts of CS on HA was8.9%. The powder X-ray diffraction (XRD) analysis confirmed that this modification methods underwent on the surface of HA nanoparticles without changing its bulk properties. HA-CS could disperse well in water solution and possess better biocompatibility than HA.Chapter3, HA was firstly treated by γ-aminopropyltriethoxysilane and amino functionalized (HA-NH2) was obtained and reacted with2-bromoisobuturyl bromide (BIBB) was coupled to the surface of HA nanoparticles to obtain ATRP initiator (HA-Br). HA-Br was used to initiate the ATRP of2-(tetracyl-beta-D-glucopyranosyl) ethyl methacrylate, the glycopolymer grafted on the surface of HA nanoparticles was obtained. The nano-fiber was prepared by blending the surface modification HA with poly(lactic acid)(PLLA) by using the electrostatic spinning method. FT-IR,NMR,TGA,XRD and TEM were used to investigate the product.