Extensional flow of mica-filled polyethylene

Extensional flow of mica-filled high density polyethylene was studied at 150°C in a Rheometrics elongational rheometer. The constant strain-rate mode at a rate of 10⁻³ to 1.0 s⁻¹, and the constant stress mode were used. The mica content was 0, 25, 40, and 60 weight percent. In both testing modes, the steady state elongational viscosities were obtained; those for the filled samples were about ten to twenty times larger than the shear viscosity at corresponding (low) rates of deformation.