Absorption of Acoustic Waves in Dilute Solutions and Dilute Suspensions of Polymers at Frequencies 10 to 300 kHz

Acoustic absorption of dilute solutions of polystyrene in xylene is measured at frequencies 10 to 300 kHz by means of the resonance reverberation method. Dynamic volume viscosity as a function of frequency is obtained for solutions of polystyrene of three different molecular weights. The data exhibits relaxational behavior in the covered frequencies. The relaxation has a much higher relaxation strength than shear relaxation predicted by the Rouse theory. The distribution of relaxation times is broad and seems to join with the acoustic relaxation at megahertz range which has been attributed by Hassler and Bauer to crank-shaft motion of polymer segments. Acoustic absorption of dilute aqueous suspensions of styrene-butadiene rubber is measured and the imaginary part of complex bulk modulus of the rubber is calculated. The loss modulus increases with increasing frequency, suggesting the loss peak due to the primary relaxation is positioned at a higher frequency.