A simplified potential energy clock model for glassy polymers

The potential energy clock (PEC) model for glassy polymers derived previously was shown to predict accurately a broad range of responses including temperature-dependent yield in different modes of deformation, enthalpy relaxation, volume recovery, and aging of the yield stress. It was, however, somewhat difficult to parameterize and employ computationally, and these points may affect its implementation and use. To facilitate acceptance, the model has been greatly simplified by keeping only necessary terms and employing some approximations. The resulting simplified potential energy clock (SPEC) model is quite easily computed and parameterized, yet faithfully reproduces the predictions of the full potential energy clock model implying that experimental responses are still accurately predicted. Such comparisons between the new model, old model, and data are presented as well as new predictions for creep. Again, the predictions are in good agreement with the experimental data. (C) 2009 Elsevier Ltd. All rights reserved.