Synthesis and <I>In-Vitro</I> Analysis of Degradative Resistance of a Novel Bioactive Composite

Abstract

The biostability of the polymer is one of the critical parameter to use them for biomaterial application. Polyurethane being one of the most compliant polymer but there are concerns regarding its resistance to degradation, particularly from hydrolysis and oxidation. The aim of this study is to synthesise a novel bioactive composite by creating a covalent linkage between polyurethane and nano-apatites and to analyse the in-vitro hydrolytic degradation of a series of newly synthesised polyurethane (PU) and polyurethane/nano-hydroxyapatite (PU/n-HA) composites. Nanoapatite powder was produced through sol–gel technique. A novel polyurethane composite material was prepared by chemically bonding the n-HA to the diisocyanate component in the polyurethane backbone by utilising solvent polymerisation. The concentration of nano-apatite was 5, 10, 15 and 20% wt/wt in polyurethane. Hydrolytic degradation of the PU and PU/n-HA composites were carried out both in deionised water and in phosphate buffer solution (PBS) having (pH 7.4) at 37 � C for a predetermined time interval of 90 days. The PU and PU/n-HA composites were physically and chemically characterised by using contact angle measurement, weight loss, Fourier Transform Infrared spectroscopy couples with Photoacoustic Sampling Cell (FTIR-PAS), Raman Spectroscopy, X-ray Diffraction (XRD) and Scanning electron microscopy (SEM). These characterisations showed that with the addition of n-HA the composite exhibits hydrophobic behaviour and degradation rate reduces due to covalent linkage between n-HA and PU. Hence it has been concluded that the degradation rate of the newly developed PU/n-HA composites can be controlled, which helps in tailor making the biomaterial for specific applications.