Activation parameters of stepped deformation of polymers

Creep rates on short deformation base lines before and after a change in temperature and stresses were measured by interferometry to determine the activation energies and activation volumes of the process. It is shown that the activation parameters of polymer creep vary not only at a macroscopic level but also within the micron-size deformation steps. The largest potential barrier corresponds to the lowest rate in a step and plays the role of a “physical node.” The results confirm the supposition that micron-size jumps (steps) of polymer deformation are caused by the nonmonotonic nature of intermolecular interactions in microvolumes of this level. Fiz. Tverd. Tela (St. Petersburg) 40, 1635–1638 (September 1998)