Mechanical Properties And In Vitro Biocompatibility Study Of Biomedical C/C Composites

Abstract:Carbon/carbon (C/C) composite in this study was prepared by chemical vapor infiltration (CVI) process using different density needled felt as performs. Re-densification and drilling hole at the center were conducted. Mechanical strength and modulus changes as well as failure behavior were analyzed. Pyrolytic carbon and silicon carbide coating were deposited on C/C composites surface respectively, then the composite was soaked in the simulated body fluid and co-cultured with human osteoblast cell. The mineral induction ability of C/C composite and its influence on cell adhesion and growth were observed, and the mechanism was discussed preliminarily. At the same time, through sol-gel method, hydroxyapatite (HA) coating was prepared on the surface of C/C composites with pyrolytic carbon deposited on their surface. Cell culture experiment was also carried out. The main conclusions are as follows:In this experiment, mechanical strength including bending, shear and compression strength and modulus increased with perform density increasing. Re-densification could improve the mechanical properties of C/C effectively. Drilling hole at the center would significantly reduce the flexural strength of C/C composites with needled felt perform. The main reason was the decrease of section area, which would be remedied by increasing the width of section but could not be eliminated.Pyrolytic carbon and silicon carbide coatings were conducive to change the surface layer from porous structure into compact construction. The cell compatibility of pyrolytic carbon coating was the best and that of silicon carbide coating is better, compared with that of no coating on the surface. The main reason is that the sags between pyrolytic carbon particle were in favor of cell adhesion, and the smooth spherical surface was suitable for the growth of osteoblast pseudopodia.The grain size of obtained HA was about50nm. Hydrogen peroxide and ammonium persulfate pretreatment could effectively improve the uniform distribution of HA coating on the surface of C/C composites. Cell culture experiment results showed that the PyC+HA double layer coating had good cell activity.