MATHEMATICAL-MODEL FOR VISCOSITY IN CAPILLARY EXTRUSION OF 2-COMPONENT POLYBLENDS

Experimental viscosity of two component polyblends is correlated to a mathematical model by introducing a frictional correction factor at the interfaces between two unlike adjacent compositions. It is found that the phase structure as well as the elastic behavior of the compositions can greatly affect the viscosity of the system and make the estimation more complicated. Fair agreement between theory and experiment is found, however, for less compatible systems, such as the PP/PS and PE/PS systems. A lesser degree of acceptance is shown for systems containing an elastic component, such as PVC/ABS and PS/PB systems. The confused phase structure of the systems as evaluated by the electron microscopic observation often causes an increase in viscosity of the systems and thus a deviation from the theoretical calculation. © 1979, The Society of Polymer Science, Japan. All rights reserved.