The shear and transient isothermal extensional flow properties of a semicrystalline and an amorphous thermotropic liquid crystalline polymer are investigated. Independent estimates of the relationship between extensional viscosity and strain rate are derived from the measurement of (i) pressure loss in converging flow and (ii) filament tension in isothermal fibre spinning. The former material, a copolyester of hydroxybenzoic acid and naphthoic acid, flows readily in extension and shear. Results for the amorphous material suggest the need for a more detailed investigation of important elongational flow properties.
- elongational flow
- extensional flow
- thermotropic liquid crystalline polymers