Torsional dilatometry of polymer networks in equilibrium

In the work presented the authors have measured the volumetric response to torsional deformations of these networks in the temperature region near the conventional glass transition and after annealing to the equilibrium volume. From the experiments it is clear that the volume change on torsion of the equilibrium D400 epoxy network near its glass transition is positive (dilatational). The volume change increases as the temperature decreases and, at constant temperature, as the deformation increases. The volume change at a given deformation relaxes to zero much more quickly as the temperature increases.