Influence of Surface Modification on the Fabrication of Polymer / Hydroxyapatite Bone Composite by means of Biomimetic Process

Ethylene-vinyl alcohol copolymer / hydroxyapatite (EVOH / HAp) composite as bone material was fabricated by using a biomimetic process in simulated body fluid (SBF). SEM micrographs and EDS analysis confirmed that bone-like HAp partially displaced by Mg2+, K+ and Na+ formed reasonably over the EVOH substrate, and that the thickness of HAp layer should depend strongly on the SBF content and soaking period. The surface modification process was applied so as to improve the HAp forming ability, in which CaCl2 and K2HPO4 solutions were used for a novel alternate soaking process. SEM micrograph of the modified surface demonstrated that amorphous calcium phosphate layer successfully formed over the surface and subsequently induced HAp layer with 3-4μm. Ultrasonic irradiation process was also applied on polyvinyl alcohol powders, suggesting that wave frequency and irradiation period should exert an influence on the HAp forming ability.