Output details

Imaging and analysis of wave type interfacial instability in the coextrusion of low-density polyethylene melts

This collaboration with University of Zlin provides the first ever characterisation of instability generation at the confluence of two melt streams, at different entry angles, in multi-layer extrusion, a widely used process for polymer multilayer film production. Leading edge rheo-optical experimentation (Bradford) in a unique windowed coextrusion die demonstrated instabilities, including measurement of oscillating stress fields (stress birefringence) and disturbances to velocity fields (laser lit particle tracking velocimetry). This was combined with leading computational analysis (Zlin) to show clearly the cause of instabilities; such understanding can assist process control and die design, and feeds into commercial Compuplast software development.