A primarily experimental research program will be carried out on the existence and growth of interfacial instabilities which can occur in the coextrusion of polymer melts. Dies equipped with pressure transducers and optical windows will be used to determine interface deformation and wall stresses in the coextrusion of various combinations of resins. Required rheological characterizations will also be carried out. A theoretical stability analysis will complement the experiments. The instabilities to be investigated are detrimental to the processing of multilayer films or fibers through coextrusion. Their understanding and control is of great importance in materials processing.
