Fabrication, processing and assessment of mechanical behaviour of hydroxyapatite (HAp) reinforced polycarbonate (PC) composite for bio-medical applications

A composite can be defined as a material having two or more chemically distinct phases, which at the microscopic scale are separated by a distinct interface. A composite have light weight, high strength to weight ratio and stiffness properties and replaces the conventional materials. Composites are finding applications in many fields ranging from construction to automotive industry and today widely in biomedical field as well. Hydroxyapatite (HAp) is a suitable ceramic material for tissue repair and replacement. In this study, ceramic composites comprising of synthetic HAp reinforced with Polycarbonate (PC) thermoplastic polymer are fabricated and tested to assess mechanical behaviour of ceramic composite. The materials may serve the purpose in biomedical engineering in respect to repair and replacement of fractured bone with artificial bone materials. Many implant materials has been made in the last three decades of metals, alloys, ceramics and polymers etc. Most metals and ceramics are much stiffer than bone tissue, which can result in mechanical mismatch (i.e. “stress shielding”) between the implant and the adjacent bone tissue. Because metals are too stiff in addition to their other biocompatibility problems, ceramics are too brittle and polymers are too flexible and weak to meet the mechanical strength while polymers are popular due to their low density, good mechanical strength, and easy formability however, low stiffness, high wear rate and low hardness limit their use in various demanding applications. To overcome these difficulties polymeric bone implants may be used. In this present work, HAp has been synthesized by wet chemical precipitation route. HAp particulates incorporated into polymer matrix through a series of processing stages involving melt compounding, granulating and micro-injection molding. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and Scanning electron microscopy (SEM). The mechanical properties such as tensile, compression, flexural, impact and hardness have been assessed for the composite varying HAp volume percentage in PC polymer. The aim is to produce a material that has similar mechanical properties to that of bone in order to achieve mechanical compatibility in the human body.