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 hydroxyapatite and a biodegradable copolymer Polyactive(TM) 70/30. Hydroxyapatite was fi rst surface modified by the polyelectrolytes polyacrylic acid or poly(ethylene-co-maleic acid) in aqueous solutions. Subsequently the surface-modified hydroxyapatite was used as filler in composites with Polyactive(TM) 70/30. The strength, elongation at break and elastic modulus of the composite in aqueous environment were significantly improved by this method. Based on these experimental results, it is believed that the interface improvement is due to hydrogen bonding and/or dipole interactions formed between polyelectrolyte molecules and polyethylene glycol segments in the polymer matrix. Due to the introduction of interfacial bonding by using such method, a new biodegradable bone-bonding composite can be made.