Rheological constitutive equations for glassy polymers, based on trap phenomenology.

The present work comprises an upgraded version of a previous research of ours, referring to the evaluation of viscoelastic functions in a broad frequency and time scale. Our analysis is based on the assumption that the polymeric structure consists of an ensemble of meso-regions, with their own energy barrier, which follows a distribution. Through a cooperative process, the meso-regions are linked to each other, and perform rearrangements by changing their positions. The time-dependent behavior is controlled by the distribution energy barriers. In the present analysis, the distribution function will be evaluated by the experimental data of loss modulus. Hereafter, the viscoelastic functions can be evaluated, with further parameters. In addition, the temperature dependence of storage and loss modulus at a constant frequency can be described within the context of the proposed model. [ABSTRACT FROM AUTHOR]