Ultrasonic velocity and absorption and shear viscosity measurements were made as a function of concentration and temperature for binary aqueous solutions of the polymer polyvinylpyrrolidone. The polymer has a molecular weight of 360 000 and was mixed with water in several concentrations ranging from 0% to 9% by weight. The frequency used was 21 MHz and the temperature range was 20 øC to 45 øC. The velocity shows a nonlinear increase with temperature and a nearly linear increase with concentration. The a/f 2 and viscosity values increase monotonically with concentration, and these values decrease with temperature. The temperature behavior, in a general sense, for the velocity and a/f 2 of the solution is similar to that of pure water. As the concentration increases from 0% to 9%, the viscosity increases by more than two orders of magnitude, while the a/f 2 value increases by less than one order of magnitude. No strong evidence of a critical concentration was observed.
Ultrasonic velocity at a frequency of 25.1 MHz was measured as a function of concentration and temperature in binary solutions of poly(ethylene oxide) and water. Absorption measurements at 21 MHz were also carried out for different concentrations and temperatures. In addition, shear viscosity was measured. The poly(ethylene oxide) has an average molecular weight of five million. Values for the velocity increase with both concentration and temperature. Both the absorption and viscosity increase with concentration, but decrease with increasing temperature.
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