Masahiro Maebayashi

Acoustic Analysis of Composite Soft Materials, II Characterization of Composite Materials Containing Glass Beads

The velocities of longitudinal, transverse and leaky surface skimming compressional wave (LSSCW) of polyvinylchloride composite materials were measured as a function of the glass bead content. The velocities of longitudinal and transverse waves for composite materials increased with the concentration of glass beads, but the velocity of LSSCW for polyvinylchloride matrix did not change. The partial specific volume and specific compressibility of glass beads dispersed in polyvinylchloride were evaluated from sound velocity and density data. These results suggest that the boundary layer has a thickness of 1–5 micrometers, and is more rigid than the polyvinyl chloride (PVC) matrix.

Development of a Quartz Crystal Microbalance System for Evaluation of Viscoelastic Properties of Thin Polymeric Films at High Temperatures

A quartz crystal microbalance (QCM) system operating at high temperatures was developed in this work. Our experimental data revealed a change in resonance frequency and dissipation factor of thin polystyrene (PS) films in the temperature range from 298 to 473 K. The thickness of PS films was estimated from the surface area of film and the amount of PS. It was found that the dissipation increased above the glass transition temperature and also increased as the thickness of PS films increased.

Evaluation of Young's Modulus for Polymer Thin Film on Isotropic Substrate by Complex V(z) Curve

The complex reflectance function of acoustic waves in the incidence angle range from 0 to 60° was calculated for polymer thin films on glass substrates with different Youngs modulus and density values. A characteristic phase change of the complex reflectance function was observed due to the existence of the polystyrene thin film on the glass substrate. The phase change appeared when the thickness of the polymer thin film was more than 0.9 µm at 300 MHz. The normalized wave number of the characteristic phase change varied sensitively with Youngs modulus and the density of the polymer thin film. The contour map of the normalized wave number was obtained from these results. The determination method of Youngs modulus of the polymer thin film by the characteristic phase change was proposed.