Preparation and characterization of crosslinked polyurethane-block-poly(trifluoropropylmethyl)siloxane elastomers with potential biomedical applications

A series of crosslinked polyurethane-block-poly(trifluoropropylmethyl)siloxane elastomers were prepared via two steps. First, poly(trifluoropropylmethyl) siloxane polyurethane (FSPU) prepolymers were synthesized with alpha,omega-bis(3-amino propyldiethoxylsilane) poly(trifluoropropylmethyl) siloxane (APFS) and toluenediisocyanate (TDI) and then capped with butanediol to generate the macromolecular FSPU diol extender. Second, polyurethane prepolymers synthesized from poly(tetramethylene oxide) and TDI were reacted with FSPU diol extenders with different ratios. The copolymers formed films through moisture curing and were characterized by Fourier transform infrared spectroscopy, DSC, dynamic mechanical analysis, TGA, mechanical testing etc. It is found that the equivalent ratio of reactants gives rise to a high molecular weight of copolymers and that low molecular weight APFS in the copolymers can form a certain number of silicon-oxygen crosslinks resulting from silicon alkoxy to produce higher tensile strength elastomers. The material thus has higher thermal stability and a more stable surface performance. The copolymers are then good candidates for biomedical applications. (C) 2013 Society of Chemical Industry