The Mechanical Behavior of Double Network Elastomers

Abstract

Abstract It was found that at low residual strains, the modulus of double network rubbers can be less than that of an isotropic elastomer of equal crosslink density. At higher residual strains, the equilibrium modulus is higher for the double network. This aspect of the behavior of networks was investigated using two phenomenological descriptions of rubber elasticity, the Mooney-Rivlin (MR) and the Roth, Martin, and Stiehler (RMS) Equations. Calculations using either approach, which make use of the independent network hypothesis, were qualitatively in agreement with the experimental data. The tensile strength of double networks based on natural rubber were found to be independent of the amount of residual strain. This is true even at higher residual strains, wherein the modulus is significantly amplified. This suggests that the conventional compromise between modulus and failure properties can be circumvented using double network rubbers. Their utilization can yield elastomers of better mechanical properties.