Production of polyurethane/nano-hydroxyapatite hybrid materials and microstructural characterization

In the present work, the polyurethane/nanohydroxyapatite hybrid materials were prepared with different content of nHA (0, 10, 20, 30, and 40% weight) as filler. The nanohydroxyapatite powders were synthesized by hydrothermal synthesis and by ultrasound-assisted co-precipitation methods. The synthesis of polyurethane was carried out by a two-step polymerization method using 1,6-diisocyanate hexane, polycaprolactone and 1,4-butanediol as precursors. The nHA was added in situ during the polymerization reaction. The structure, microstructure, specific surface and thermal stability were determinate by XRD, FTIR, SEM, DTA-TGA, DSC and water absorption measurements. The results show that the synthesized nanohydroxyapatite powders were composed of micrometric and mesoporous aggregates of nanocrystalline hydroxyapatite particles (Dc ≤ 40 nm), in addition, since nanohydroxyapatite powders are prepared via ultrasound-assisted co-precipitation showed high surface area values (97.9 m²g^-1) and homogeneous chemical composition, these ones were used for the fabrication of hybrid materials which were successfully prepared by the incorporation in situ of nanohydroxyapatite during the polymerization process. The obtained materials showed different behavior during water absorption tests as well as thermal stability as a function of filler content.