Rouse-Model-Based Description of the Dielectric Relaxation of Nonentangled Linear 1,4-cis-Polyisoprene

A detailed test of the Rouse Model has been performed oil it nonentangled 1,4-cis-poly(isoprene) (PI) by investigating the end-to-end vector dynamics by means of broadband dielectric spectroscopy. The contribution to the dielectric relaxation of the end-to-end vector dynamics was determined by subtracting the signal from the local segmental dynamics dominating at higher frequencies This signal was inferred from experiments oil higher molecular weight samples. Our results show that the Rouse model accounts remarkably well for the experimental data once the narrow distribution of molecular masses is properly accounted For The very same approach is found to provide a good description of it simultaneous dielectric/rheology experiment. Despite the overall good agreement between experiments and model predictions, small excess contributions in the high frequency side of the dielectric losses are detectable.