Synthesis and characterisation of styrene butadiene styrene-g-N-vinyl-2-pyrrolidinone for use in biomedical applications

The current contribution investigates the potential use of styrene butadiene styrene (SBS) block copolymer grafted with N-vinyl-2-pyrrolidinone (NVP) for use as a novel biomaterial. SBS-g-NVP was synthesised using UV polymerisation and analytical techniques such as differential scanning calorimetry (DSC), attenuated total reflectance infrared Fourier transform spectrometry (ATR-FTIR), dynamic thermal mechanical analysis (DMTA) and goniometry were used to characterise the grafted copolymers. The ATR-FTIR spectrum for grafted SBS-g-NVP copolymer exhibits a shoulder at 1714 cm−1, which is associated with carbonyl stretching of NVP. DSC analysis showed the grafted copolymers had broader thermographs within the butadiene rich domain resulting in increased Tg values, suggesting that grafting occurred. Confirmation of this was established by the use of DMTA, where the Tg (−90 °C) which represents the butadiene domain increased to −76 °C, thus proving grafting. The surface chemistries of the grafted copolymers have also been altered which is reflected in the goniometry results which show a dramatic reduction in contact angles (113° to 7°), which is a desired property for biomedical polymers.