Rheological Characterization and Wall Slip of Polymethylvinylsiloxane

摘要

The rheological behavior and wall slip phenomena in torsional flows of a commercial polymethylvinylsiloxane (PMVS) have been studied by using a rotary rheometer with cone-and-plate and parallel-plates fixtures. The damping function obtained from the shear stress relaxation experiment has been compared to the prediction of Doi-Edwards theory with independent alignment approximation and that of Marrucci model. In step strain deformation, maximum stress at a certain strain was always observed, suggesting that possible strain localization or stratified strain may occur inside the sample. Wall slip phenomena in steady torsional flow of a PMVS and a high-density polyethylene (HDPE) have been compared by using the same parallel-plates fixtures and gap variation. In the shear stress range of 100-5000Pa, PMVS exhibits anomalous slip behavior.