High shear strain rate rheometry of polymer melts

Citations Over TimeTop 11% of 2009 papers

Abstract

Abstract The rheology of a range of polymer melts has been measured at strain rates above those attained during conventional rheometry using an instrumented injection molding machine. Deviations from shear thinning behavior were observed at high rates, and previously unreported shear thickening behavior occurred for some of the polymers examined. Measured pressure and volumetric throughputs were used to calculate shear and extensional viscosity at wall shear strain rates up to 10 7 s −1 . Parallel plate rheometry and twin bore capillary rheometry were used to provide comparative rheological data at low and medium shear strain rates, respectively. Commercial grades of polyethylene, polypropylene, polystyrene, and PMMA were studied. Measured shear viscosity was found to follow Newtonian behavior at low rates and shear thinning power law behavior at intermediate strain rates. At shear strain rates approaching or above 10 6 s −1 , shear viscosity reached a rate‐independent plateau, and in some cases shear thickened with further increase in strain rate. A relationship between the measured high strain rate rheological behavior and molecular structure was noted, with polymers containing larger side groups reaching the rate‐independent plateau at lower strain rates than those with simpler structures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Related Papers

• → Application of Rabinowitsch Fluid Model to Pivoted Curved Slider Bearings(2013)14 cited
• → Non-Newtonian Effects on the Squeeze Film Characteristics between a Sphere and a Flat Plate: Rabinowitsch Model(2012)14 cited
• → A general model for the effective viscosity of pseudoplastic and dilatant fluids(1975)10 cited
• → Pseudoplasticity and Dilatancy in Shallow Channel Flows(1998)3 cited
• → Dry granular flows: rheological measurements of the $\mu(I)$-Rheology(2014)