Measurement of interfacial instabilities during coextrusionof LDPEs in flat dies

In flat dies, measurement of interfacial instabilities during coextrusion process of low density polyethylenes (LDPEs) were discussed. Difference between zig-zag instabilities related to shear stress and wave instabilities related to the merge point of coextruded LPDEs were studied. The experiment was conducted on a standard multi-manifold coextrusion pilot plant line and with three LPDE materials. It was found that the shapes of the interfacial instabilities (zig-zag and wave) were same and also the origin of these instabilities was from the same part