Production of hydroxylapatite reinforced polymer composites for biomedical applications

In this study, hydroxylapatite (HAp) reinforced polymer composites were produced and evaluated to be used in bone implants. The aim was to produce a material that has similar modulus of elasticity (E) and other mechanical properties to those of bone in order to achieve mechanical compatibility in the body. Hydroxylapatite was mixed with high density polyethylene (HDPE) and polypropylene (PP) in different amounts. The resulting composite materials were injection molded into standard tensile and impact test specimens and their mechanical properties were examined. Stiffness and hardness of the composites were increased toughness, percent elongation and impact energy were decreased with increasing HAp content. No significant change was observed in ultimate tensile strength while an increase was significant in the yield strength related to HAp content. PP composites were found to have better impact properties in spite of more ductile behavior of HDPE composites under tension. Although the problem of mechanical compatibility in bone implants has not totally been solved, hydroxylapatite reinforced polymer composites are suggested as promising alternatives to traditional implant materials.