UNDERSTANDING RHEOLOGY AND TECHNOLOGY OF POLYMER EXTRUSION

Polymer basics. Viscosity and unidirectional melt flows. Shear thinning, viscous dissipation, Generalized Newtonian Fluid, power-law. Viscoelasticity, normal stress differences, elongational viscosity, extrudate (die) swell, stress relaxation and relaxation time. Sharkskin, melt fracture, die lip build up (drool). Rheological measurements (melt Index, capillary, Rabinowitsch and Bagley corrections, cone-and-plate, parallel plate, oscillatory, …