In situ synthesis of bone-like hydroxyapatite/polyamide 6 nanocomposites

BACKGROUND: Polymer/hydroxyapatite (HA) nanocomposites have emerged in recent years as a new class of biomaterials that can be used as artificial bone. Compared to pure HA or HA-based bioceramics, and metallic implants, they exhibit good plasticity, improved toughness and good mechanical compatibility with natural bone. Compared to their microcomposite counterparts and the pristine polymer matrix, they show increased tensile strength and modulus, and enhanced bioactivity. RESULTS: In this study, polyamide 6 (PA6)/nanoscale HA (n-HA) nanocomposites were prepared via in situ hydrolytic ring-opening polymerization of E-caprolactam in the presence of newly synthesized n-HA aqueous slurry. The synthesized n-HA, which is similar to bone apatite in chemical composition, microscopic morphology and phase composition, dispersed uniformly in the composites even if its loading was up to 60 wt%. The PA6/n-HA composites show a similarity to natural bone in chemical composition to a certain extent. Mechanical tests show that the composites are reinforced considerably by the incorporation of needle-like n-HA, and the composites have mechanical properties near to those of natural bone. CONCLUSION: The PA6/n-HA nanocomposite with high n-HA content shows a similarity to natural bone in terms of chemistry and mechanical properties. This makes it a possible candidate for biomaterials suitable for bone repair or fixation. (C) 2008 Society of Chemical Industry