Tensile stress measurements of dilute polymer solutions containing traces of salts and dyes

Tensile stress studies were made on dilute solutions of poly(ethylene oxide) and polyacrylamide using a fiber spinning apparatus to investigate the interaction of polymer molecules with the flow field. The addition of dyes or metal ions to the solutions has a considerable influence on the tensile stress. These ingredients normally cause contraction of the polymer coils and stiffen the molecular chains. One additive, Congo Red, markedly increased the tensile stress of poly(ethylene oxide) solutions.