Preparation And Properties Of Carbon Fiber Reinforced Si-HAC And Its Biocomposites

Hydroxyapatite (HA) is the main inorganic component of vertebrates in bones and teeth with similar structure, which contains 77% in body bones and 97% in dental bones. The bone cells can react with HA in its surface to form good combination intensity and good stability due to its excellent biocompatability, bioactivity, conductibility and induction of bone, etc. It shows that the HA has been widely used in human hard tissue repair and replacement because it can take effect in inducing the bone cells to grow and metabolize gradually, so it is the kind bioceramic which can combine with organism bones and teeth. However, HA only used in alveolar ridge augmentation, ear bones replacement and maxillofacial bone repair in virtue of the weak intensity and repeatability of HA itself. Hence, it is important to be reinforced and toughened.Nano-Si-HA powders sintered at 800℃for 3h were prepared by the microwave chemical reaction process using calcium nitrate [Ca(NO3)2·4H2O], ammonium dibasic phosphate [(NH4)2HPO4], carbamide and ethyl silicate;tetraethyl orthosilicate(TEOS)as raw materials. The results show that the particles average size display a trend of decreasing firstly and then increasing with Ca(NO3)2·4H2O solution concentration. The particles average size decrease with the increasing of reaction time and temperature. The smaller particles were easy to obtain by ball grinding the raw materials and products and extending the aging time. The as-prepared products washed by alcohol anhydrous are helpful to disperse.Carbon fiber reinforced silicon-substituted hydroxyapatite bone cements (Cf/Si-HAC) biocomposites were prepared using a buffer solution of acrylic acid and itaconic acid as gelling agent. The results show that the flexural strenth display a trend of increasing to a maximum and then decreasing with the carbon fibers volume fraction, silane coupling agent KH-550 mass fraction and sodium citrate content. When the carbon fibers volume fraction, silane coupling agent KH-550 mass fraction and sodium citrate content reaches 30%,0.8% and 25%, respectively, the flexural strength reaches the maximum value of 43.8 MPa.The porosity of Cf/Si-HAC biocomposites decreases firstly and then increases (61%-63%) with the increasing of Si content, which is opposite with the flexural strength. When the Si mass fraction is 4%, the porosity of the composite reaches the mimimum of 49%. The porosity increases (45%-68%) with sintering temperature, it shows that the as-prepared composites are conform to body bones.The setting time of the Cf/Si-HAC increased almost linearly from 6min to 15min with the Si content.Carbon fiber reinforced polymethyl methacrylate (PMMA)-polymethyl acrylate (PMA) biocomposites (Cf/Si-HAC/PMMA-PMA) were prepared by suspension polymerization process using polymethylmethacrylate (PMMA), methyl methacrylate (MMA) and Si-HA powders as raw materials, potassium persulfate (KPS) as initiator. The results show that the flexural strength and compressive strength of the as-prepared Cf/Si-HAC/PMMA-PMA composites both display a trend of increasing firstly and then decreasing with increasing of the PMMA/PMA volume ratio, KPS mass fraction, W/O volume ratio, the reaction temperature of solutions and carbon fibers volume fraction, and the compressive strength is bigger than the flexural strength. When the PMMA/PMA volume ratio, KPS mass fraction, W/O volume ratio, the reaction temperature of solutions and carbon fibers volume fraction reaches 8/2,1.5%,3/1,80℃and 1.5%, respectively, the flexural strength and compressive strength Cf/PMMA-PMA composite arrived to a maximum of 109.5Mpa and 239.8MPa, 111.7Mpa and 240.5MPa,110.8Mpa and 240.6MPa,110.8Mpa and 240.2MPa, 110.9 Mpa and 240.8MPa.Carbon fiber reinforced chitosan and Si-HA biocomposites (Cf/Si-HAC/CS) were prepared by suspension polymerization process using chitosan and HA as raw materials. The results show that the flexural strength and compressive strength of the as-prepared Cf/Si-HAC/CS composites both display a trend of increasing firstly and then decreasing with increasing of the Si-HA/CS volume ratio, gultaraldehyde cross-linking mass fraction, reaction temperature of solutions and carbon fibers volume fraction, and the compressive strength is bigger than the flexural strength. When the Si-HA/CS volume ratio, gultaraldehyde cross-linking mass fraction, reaction temperature of solutions and carbon fibers volume fraction reaches the 2/20,0.4%,60℃and 1.5%, respectively, the flexural strength and compressive strength of the Cf/HA-CS composite arrived to a maximum of 65.57Mpa and 76.58MPa,70.10Mpa and 86.32MPa,70.08Mpa and 92.34MPa and 62.12Mpa and 105.15MPa.The surface of the as-prepared Cf/Si-HAC/PMMA-PMA and Cf/Si-HAC/CS biocomposites were both covered by Si-HA when they were immersed from 1 day to 28 days in simulated body fluid (SBF), and the mechanical properties almost no changing. It shows that the two biocomposites not only shows the excellent bioactivity, but also the mechanical properties of them have almost no change in SBF solutions.