Fundamental aspects of rubber-elasticity in real networks

Based on the van der Waals-equation of state a characterization of the elastic properties of molecular networks in the total range of strain is presented by the use of Mooney-Rivlin plots. This discussion elucidates the importance of finite chain extensibility as well as global interactions for a quantitative interpretation of the deformation properties of molecular networks. An interpretation of the so-called Mooney-Rivlin coefficients in terms of the van der Waals-parameters delivers at least a novel, yet very consistent understanding of simple extension of swollen networks.