Abstract
Segmented polyurethane films purified by the extraction with methanol were subcutaneously implanted in the back of rats for 21 months. The surface characteristics, mechanical properties and intrinsic viscosity of the retrieved polyurethane films were examined. The opecification appeared on the film surface after 12 weeks of implantation and then developed gradually. However, any apparent fragmentation or damage was not observed during implantation. The ATR-FTIR analyses of the film surface revealed spectral changes characteristic of degradation of polyurethane. Reduction of the bands due to polyether, appearance of ester carbonyl band and reduction of non hydrogen bonded urethane carbonyl band suggested that hydrolytic and oxidative deterioration occurred on surfaces. It is considered that the degradation progressed gradually from the surface to the bulk of film after implantation, since the tensile strength decreased with time and the elongation at failure diminished definitely after 10 months.
