DIE ENTRY FLOW OF REINFORCED POLYMERS

The model describes the contributions of extensional and shear flow to the pressure drop at convergences, such as die entries, nozzles and mould gates for reinforced melts under injection moulding conditions. Fiber and molecular orientation lead to high extensional viscosities and hence large pressure losses with reinforced polymers. The model treats the flowing melt as an anisotropic fluid with extensional and shear flow governed by independent power law relations. Use of the model with real systems is described and power law constants are given for some commercial reinforced polymers.