Nonlinear viscoelasticity of Hydrothane®

The nonlinear viscoelastic behaviour of Hydrothane®, a hydrophilic polyurethane used for biomedical applications, has been studied. The material has been tested in stress-relaxation experiments in a range of deformation up to 25%. Isochrone curves have been predicted by using the rubber elasticity theory and separating strain and time effect. Stress strain curves obtained at different strain rates have been interpreted introducing strain rate dependent scaling factors.