Abstract

The present research is focused on the study of a series of polyurethane/nano-hydroxyapatite composites with different nano-hydroxyapatite (nHA) compositions (0, 10, 20, 30 and 40 %wt). Mechanical, biodegradability and bioactivity properties of composites were evaluated. Tensile tests were performed using a dynamic mechanical analyzer (DMA). Biodegradability and bioactivity studies were done by immersion into phosphate buffered saline (PBS) and simulated body fluid (SBF) solutions respectively. Both biodegradability and bioactivity behavior of specimens were monitored by gravimetric method and morphologically characterized by Scanning Electron Microscopy (SEM). Mechanical test results showed that both pure polyurethane and the 10 wt% nHA composite presented similar Young’s modulus of 4.4 and 4.7 MPa, respectively. On the other hand, at higher nHA contents, the composites became relatively brittle showing Young’s modulus from 6.6 to 8.3 MPa values. The biodegradation rate increased as a function of nHA contents. In that way, polyurethane and composite containing 10 and 40 wt% nano-hydroxyapatite lost weight about 3 and 4wt%, respectively during 56 days of immersion. Study of bioactivity revealed that the composites exhibits advantages compared with polyurethane. The formation of bone-like apatite microstructure was corroborated by X-Ray Diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) coupled energy dispersive X-ray (EDS) analysis.

Key words: Polyurethane, nano-hydroxyapatite, biodegradability, bioactivity, mechanical properties.