Studies on the Stability of a Styrene-Butadiene Copolymer for use in Biomedical Applications

Two samples of commercially-available styrene-butadiene block copolymers (SBC) were tested for suitability for use in biomedical applications. A 30% sample and a 40% sample of styrene-containing polymers with very similar molecular weights (approximately 300,000) were characterized before and after being placed in a physiological serum for a period of six months. SEM, FTIR, and atomic absorption spectroscopy were used to characterize the polymers. Scanning and transmission electron micrographs showed that the SBC's morphology was clearly affected by the serum. A difference was observed with the higher styrene-containing polymer which showed no degradation of the elastomeric portion of the copolymer, whereas the 30% sample showed that considerable degradation occurred in this area. Atomic absorption results showed a clear difference in the capability of both materials to absorb K ⁺ , Na ⁺ and Caions with a clear advantage for the 40% styrene-containing material. FTIR results indicate that both polymer samples degraded in the serum, showing loss of both the polystyrene and polybutadiene portions, as well as oxidation of the double bonds in the latter.