Investigation of the interfacial instabilities in the coextrusion flow of PE and PS

Rudy Valette (1) , Patrice Laure (2) , Yves Demay (2) , Jean-François Agassant (1)

1 CEMEF - Centre de Mise en Forme des Matériaux
2 INLN - Institut Non Linéaire de Nice Sophia-Antipolis

The interface instability of the coextrusion flow of a polyethylene and a polystyrene is experimentally studied with industrial and laboratory equipments for various flow rates and temperature. Stable and unstable coextrusion conditions are identified as a function of flow rate ratio, shear rate and temperature. It is found that temperature and flow rate ratio are the most relevant parameters. Experimental results are then compared with stability analysis assuming White-Metzner constitutive equations. Agreement is fair at temperatures of 180 °C and 200 °C. However the longwave stability analysis is not sufficient to predict all experimental data.

Mots clés: polyethylene; polystyrene; analysis; article; coextrusion; equipment; experimentation; flow; flow rate; industrial equipment; interfacial instability; laboratory; mathematical analysis; molecular stability; physical phenomena; prediction; shear rate; temperature; White Metzner equation

Domaines: Matériaux

Rudy Valette, Patrice Laure, Yves Demay, Jean-François Agassant. Investigation of the interfacial instabilities in the coextrusion flow of PE and PS. International Polymer Processing, 2003, 18 (2), pp.Pages 171-178. ⟨hal-00613066⟩