SURFACE MODIFICATION OF HYDROXYAPATITE TO INTRODUCE INTERFACIAL BONDING WITH POLYACTIVE(TM)-70 30 IN A BIODEGRADABLE COMPOSITE/

A method was developed to improve the interfacial bonding between hydr oxyapatite and a biodegradable copolymer Polyactive(TM) 70/30. Hydroxy apatite was fi rst surface modified by the polyelectrolytes polyacryli c acid or poly(ethylene-co-maleic acid) in aqueous solutions. Subseque ntly the surface-modified hydroxyapatite was used as filler in composi tes with Polyactive(TM) 70/30. The strength, elongation at break and e lastic modulus of the composite in aqueous environment were significan tly improved by this method. Based on these experimental results, it i s believed that the interface improvement is due to hydrogen bonding a nd/or dipole interactions formed between polyelectrolyte molecules and polyethylene glycol segments in the polymer matrix. Due to the introd uction of interfacial bonding by using such method, a new biodegradabl e bone-bonding composite can be made.