Abstract
We strictly assess the validity of the familiar Mooney-Rivlin approach to the strain energy density function (W) on the basis of the quasi-equilibrium uniaxial and biaxial deformation data of end-linked poly(dimethylsiloxane) networks prepared from the solutions with various precursor concentrations. The constants C1 and C2 in the Mooney equation (W = C1 (I1 − 3) + C2 (I2 − 3)) are obtained from the intercept and slope of the linear correlation in the Mooney-Rivlin plots for the uniaxial data, respectively. The biaxial stress-strain relations estimated by the Mooney equation are far from the real behavior for all samples. It is clearly demonstrated that the Mooney-Rivlin approach, which has still been employed due to the simplicity in many studies, is unsuccessful to deduce the form of W.
