Synthesis and Characterization of Alumina-ChitosanHydroxyapatite Biocomposites for Load Bearing Application

Abstract

This study investigated the influence of reinforcing hydroxyapatite (HA) with alumina (Al) and chitosan nanofiber (CH) to enhance its usefulness in load bearing application. Commercial alumina was used while chitosan fiber and hydroxyapatite were synthesized from cowry shells and limestone respectively. The developed composites were characterized with a view to assessing theirsuitability for use as medical implants in load bearing capacity. It was observed that the optimum compressive strength obtained was 181.73 MPa, tensile strength of 172.67 MPa, hardness value of 529.21 HV, fracture toughness of 7.42 MPa.m1/2 , elastic modulus of 8.23 GPa and bending strength of 175.51 MPa. Increasing volume fractions of Al-CH resulted in decrease in compressive strength, hardness and elastic modulus of hydroxyapatite while its tensile strength, bending strength and fracture toughness increased. The result obtained from the Fourier Transform Infrared Spectrometry revealed that the intermolecular hydrogen bond and chelate interaction between the constituents contribute to the good mechanical properties of the composite. X-Ray Fluorescence analysis result indicates that their chemical compositions contain ions which are found in the physiological environment. The dispersion of the alumina-chitosan nano fiber in the HA matrix as revealed by the Scanning Electron Microscope micrographs result in the formation of interfaces which activates different mechanisms that improve the strength of HA. The optimum mechanical property was obtained at 20-20-60 Al-CH-HA composite. Hence, this composite will be a suitable material for load bearing application.