A constitutive model for strain-crystallising Rubber-like materials

In the present paper, a constitutive model for strain-crystallising rubber is proposed. The constitutive behaviour is formulated in terms of a strain energy function, where the full network approach is adopted. The Arrhenius equation provides the basis for the crystallite nucleation law. The full network approach allows for the development of an anisotropic crystal structure. The model was applied to experimental results from uniaxial tensile tests. Strain-crystallisation causes a hysteresis in the stress-stretch relation, but according to the model predictions, the effect of crystallisation is not sufficient to explain the mechanical hysteresis observed in the tensile tests. Hence, additional viscoelasticity associated with amorphous polymer chains must be included. The model was fully able to predict both the stress vs. stretch relations and the crystallinity vs. stretch relations from the experiments. (C) 2010 Elsevier Ltd. All rights reserved.