INFLUENCE OF NORMAL STRESS DIFFERENCE ON POLYMER DROP DEFORMATION

Polypropylene drops of varying viscosity and elasticity were sheared i n a polystyrene matrix. Two transparent, counter-rotating parallel dis ks provided simple shear flow. By adjusting the speed of one disk the drop center was fixed in the laboratory frame and deformation followed via high magnification video camera. It was found that with high matr ix elasticity drops of the minor phase stretched perpendicular (x(3)) to the flow direction (x(1)). This is the first report of widening of drops in shear flow. An analytical relation was established between th e second normal stress differences of the phases and degree of widenin g. The formation of sheets and the phenomena of widening results in a larger than affine area generation.