Gradient semi-interpenetrating polymer networks based on polyurethane and poly(vinyl pyrrolidone)

Gradient semi-interpenetrating polymer networks (gradient semi-IPNs) were synthesized using polyurethane (PU) and poly(vinyl pyrrolidone) (PVP). The materials were characterized with respect to thermodynamic miscibility, IR-spectroscopy, mechanical properties and morphological structure. The positive values of Gibbs free energy indicated that the polymeric systems were thermodynamically immiscible. The gradient semi-IPNs were shown to have unique mechanical properties dependent on the composition and the subsequent degree of microphase separation. Given the ability to control both the mechanical properties and surface chemistry, these materials offer the potential for further development as biocompatible biomedical materials for the fabrication of medical implants.