The velocity profiles of molten polymers during laminar flow

Summary The velocity profiles of the flow of some polymeric melts (low density polyethylene, two high density polyethylenes and a polydimethyl siloxane) through a rectangular slit have been measured. The velocity profiles measured were in good agreement with those calculated from the flow curves. In agreement with the assumption usually made for laminar flow, the velocities at the wall were found to be zero in all cases. This was true even during melt fracture for a low density polyethylene and a polydimethyl siloxane.