Small angle light scattering analysis of morphology development of a modelimmiscible polymer blend in transient slit-contraction flows

A novel experimental system is developed to study the morphological develop ment of a model immiscible polymer blend system (polyisobutene-polydimethyl siloxane) in complex, transient flows. A simplified analysis technique usin g small angle light scattering probes the microstructure of the blend in si tu and provides information concerning the overall deformation state of the blend. Depending on the viscosity ratio of the blend, the morphological ev olution is more strongly influenced by either the transient shear or elonga tional component of the Row. Steady state modeling is also applied to descr ibe these transient Rows. The models are able to predict the general trends seen in the experimental data including the effect of changing blend visco sity ratio and initial morphology. (C) 2001 The Society of Rhelogy.