Abstract
The velocities of the longitudinal and the transverse waves of polyvinylchloride (PVC) composite materials containing micas or glass beads were measured by an acoustic pulse method using a time-to-amplitude converter. The morphology and the velocity of leaky surface skimming compressional wave (LSSCW) propagating near the surface of the PVC matrix were obtained by using a scanning acoustic microscope. The longitudinal and the transverse wave velocities increased with the concentration of the particles dispersed in the PVC matrix. The concentration dependence of the LSSCW velocity was not observed in the concentration region investigated here. The partial specific volume and the partial specific adiabatic compressibility of the particles dispersed in PVC were estimated from density data and velocities of the longitudinal and the transverse waves. The partial specific volumes were nearly equal to the specific volume of the particle dispersed. The partial specific adiabatic compressibility of the particles was almost zero in all samples. These results suggest that the boundary layer has a thickness of a few micrometers, and is more rigid than the PVC matrix.
