Abstract
A simple but efficient processing method for shaping intricate bioceramic green bodies has been developed by using natural rubber latex as binder. Different shapes of hydroxyapatite Ca~10~(PO~4~)~6~(OH)~2~ (HAP) were molded from a composite formulation containing wet precipitated HAP, natural rubber latex (NRL), and a stabilizer. On controlled heat treatment followed by sintering, dense shapes of HAP contours were obtained. The thermal degradation profile of HAPβNRL composites shows that NRL degrades slowly without any abrupt exotherm. The results of energy dispersive Xβray analysis together with inductively coupled plasma (ICP) analysis indicate that the inorganic residue of NRL does not contain any heavy element. The sintered density of the samples increased with increased HAP content in the formulation and percentage shrinkage reduced accordingly. On varying the HAP content in the formulation from 35 to 95 wt %, the compositions with 85, 90, 92, and 95 wt % HAP showed better flexural strength in the range 40β54 MPa and a flexural modulus value in the range 36β50 GPa. The fracture morphology, as observed by the scanning electron microscope confirms that with increased HAP content in the formulation the sample microstructure attains higher uniformity. The Vickers microhardness for the samples sintered at two different temperatures (1150 and 1250Β°C) showed that hardness increases with increase in the sintering temperature with a maximum for the highest HAP loaded formulation. Β© 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2006.