A Fundamental Study of the Rheological Properties of Glass‐Fiber‐Reinforced Polyethylene and Polystyrene Melts

Abstract

Shear viscosity,shear flow normal stresses, and elongational viscosity have been investigated for glass‐fiber‐filled high‐density polyethylene and polystyrene melts. Viscosity measurements are consistent in cone‐plate and capillary instruments Normal stress coefficients increase more rapidly with glass fiber content than the shear viscosity, especially at low deformation rates. Elongational viscosities are very high at low elongation rates but decrease rapidly with increasing deformation rate. Mechanisms are proposed to explain these observations.