EXPERIMENTAL INVESTIGATION AND SCALING LAW ANALYSIS OF DIE SWELL IN SEMIDILUTE POLYMER-SOLUTIONS

We report on systematic measurements of die swell in semi-dilute hydro lyzed polyacrylamide solutions. The solutions are extruded in a buoyan cy bath to reduce the influence of the interfacial and gravitational f orces. The experimental results are analyzed in the frame of the Tanne r's model which considers that the elastic recovery is the leading con tribution to swelling; from the jet diameter at maximum swelling, we d etermine the shear compliance of the solutions. The results are in goo d agreement with the scaling predictions reported in the literature. T he shear compliance exhibits a Rouse-like behaviour even though the sc aling of the viscosity is that of semi-dilute entangled solutions. (C) 1997 Elsevier Science B.V.