Title: Tensile properties and microstructural analysis of spheroidized hydroxyapatite- poly (etheretherketone) biocomposites Authors: M.s. Abu Bakar, P. Cheang, K.A. Khor
Journal: Materials Science and Engineering A345 (2003) 55-63.
In the present article, the authors investigate the use of flame spheroidized hydroxyapatite particulates in a PEEK polymer for usage as bone analogue materials. Metallic implants have been used for orthopedic implants in the past, but polymeric implants have been explored due to stress-shielding issues associated with metallic implants. Wolf’s Law states that if bone is not subjected to mechanical stimuli, then it will be absorbed (Uhthoff and Dubuc, 1971). Therefore, it is important to develop a material that matches the modulus to minimize stress shielding and the formation of callus during healing. PEEK is a high performance thermoplastic with good mechanical properties, good chemical and fatigue resistance, and high temperature durability. Previous focuses have been on the use of fibers as the reinforcing materials in orthopedic applications; however, reinforcements can particulates can also be employed such as bioglass, A-W glass ceramic, and hydroxyapatite. These have reported to produce composites with a modulus that has lower bounds of cortical bone and also exhibits bioactivity (Wang 1994). In this study, the authors experimentally examine a hydroxyapatite reinforced PEEK composite and addressed the processing, tensile, and microhardness properties related to the microstructural feature and compare their results to cortical bone. Composites of up to 40% volume HA were prepared by incorporating the HA particles into PEEK and manufactured using injection molding. The ashing of the composites were carried out by thermogravimetric analysis. Differential scanning calorimetry was used to evaluate the degree of crystallinity, both in the skin and core region of the molded specimen. Tensile testing was performed...
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