Prediction of impact properties of polyolefin foams

The mechanical response of PP foam in a wide range of strain rate has been studied. The linear and non linear viscoelastic behaviour has been analized. The material has been tested in creep and dinamico-mechanical experiments and the correlation between strain rate effects and viscoelastic properties of the foam has been obtained using viscoelasticity theory and separating strain and time effect. A scheme for the prevision of stress strain curve at any strain rate has been developed introducing a strain rate dependent scaling factor.