Journal of Chemical Physics, Vol.104, No.22, 9220-9233, 1996
Molecular Theory of the Yield Behavior of a Polymer Gel - Application to Gelatin
A microscopic model for the endopoint separation dependent scission rate of a polymer connection in a network is developed. The predicted dissociation rate is proportional to the exponential of the bond force, which is in line with experiments. This atomistic description is thereupon incorporated in a mesoscopic theory to describe strain hardening and failure of physical gels. The resulting theory has been analyzed by a new numerical algorithm, which is some 100 to 1000 times faster than the algorithm described in the literature. We applied this theory to gelatin. To arrive at the correct nonlinear rheologic behavior of the gel, the non-Gaussian nature of the polymer endpoint distribution has to be taken into account. There are four important physical quantities that, describe the nonlinear rheology of gelatin. For relatively small shear strain (0