Synthesis and characterization of Chitosan/Hydroxyapatite (70/30) Nano-Composites

Abstract

In this research work, (70/30) nanocomposites of Chitosan biopolymer and Hydroxyapatite (HA) ceramic powder were synthesized by insitu co-precipitation technique combined with double step stirring. Initially medical grade chitosan was extracted in the laboratory using locally available shrimp specices Penaeus Monodon. Analytic grade acetic acid, H3PO4 and Ca(OH)2 were used as starting materials. At first, chitosan was dissolved in acetic acid and mixed with required amount of H3PO4 acid. Then the chitosan / H3PO4 solution was added drop wise into the highly alkaline Ca(OH)2 suspension. During the addition chitosan precipitated with hydroxyapatite by forming the chitosan/ hydroxyapatite composite. Finally, the suspension pH reached 6.0-6.5 range, after the complete addition of the solution. Synthesized composite was characterized using Fourier Transform Infrared Spectroscopy (FTIR), Xray diffraction (XRD), thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA). The XRD spectrum demonstrated relevance peaks of chitosan and HA in composite. FTIR spectrum of composite showed the characteristics bond energies of chitosan sample and hydroxyapatite sample. Each characterization techniques confirm the existence of chitosan and FLA in the composite. The size of the HA crystals embedded in composite was calculated using Scherrer formula and it was found to be ~55 nm.