ACOUSTIC PROPERTIES OF TERNARY-SYSTEMS PO LY(VINYL CHLORIDE)-POLY(VINYL BUTYRAL)-DIBUTYL PHTHALATE

The effects of plasticizer on the propagation velocities of longitudin al and shear ultrasonic waves, their attenuation coefficients in the p oly(vinyl chloride)-poly(vinyl butyral)-dibutyl phtalate (PVC-PVB-DVP) blend were studied. The most significant variations in the propagatio n velocity of longitudinal ultrasonic waves are observed for a dibutyl phtalate contents below 2 vol %. The concentration dependence of the propagation velocity of shear ultrasonic waves is characterized by a m onotonic decrease in the velocity with increasing the dibutyl phtalate concentration in the system. The results of calculations indicate, th at in the plasticozes concentration range below 5 vol % the value dyna mic viscosity exceeds those in the PVC-PVB and PVB-DBP systems and is comparable with the values for the PVC-DBP system. Within the framewor k of the model of isotropic dielectric, theoretical estimations are ob tained for dissipative energy losses, shear and bulk viscosity, relaxa tion time, and dimensions of the segment involved in the motion under the action of a force field.