Entanglement effects in defect-free model polymer networks

The influence of topological constraints on the local dynamics in crosslinked polymer melts and their contribution to the elastic properties of rubber elastic systems are long standing problems in statistical mechanics. Polymer networks with diamond lattice connectivity are idealized model systems which isolate the effect of topology conservation from other sources of quenched disorder. By studying their behaviour in molecular dynamics simulations under elongational strain we are able to measure the microscopic deformations as well as the purely entropic shear moduli. In our analysis we make extensive use of the microscopic structural and topological information available in computer simulations and present quantitative tests of the concepts underlying most statistical mechanical models of rubber elasticity.