RHEOLOGICAL STUDY OF POLY(ETHYLENE OXIDE) IN AQUEOUS SALT-SOLUTIONS AT HIGH-TEMPERATURE AND PRESSURE

The effects of pressure and temperature on the rheological properties of poly(ethylene oxide) (PEO) aqueous solutions, with and without adde d inorganic salts, are reported. A slight decrease of the viscosity at low temperatures and an increase of the viscosity at high temperature s with increasing pressure were noted. However, the most striking effe ct was the lowering of the phase separation temperature with increasin g pressure, which manifested itself in large changes in the viscosity of the solutions. This effect is proposed to be due to the lowering of the solvent quality of the water for PEO, brought about by the disrup tion of the hydrogen bonding in the water which occurs on increasing t he pressure.