Dielectric absorption at submillimetre wavelengths due to collisional polarization in polystyrene

Abstract

Measurements of the dielectric properties of glassy polystyrene at submillimetre wavelengths show that a vibrational-collisional polarization occurs almost as easily as in liquid benzene or toluene. The collision parameters of the linked phenyl groups resemble benzene more closely than toluene. The effective collision dipole is shown to vary directly as T^½, confirming the nature of the process responsible and forming the first observations of such collisions over a wide temperature range. Mixtures of polystyrene with carbon tetrachloride show an enhanced collision polarization and decreased collision frequency, due to contact charge transfer interaction during the repulsive stages of the collision. However, the effect is less than observed in toluene where no chain controls the phenyl-group separations. A commercial sample of polystyrene, in which autoxidation products and lubricant have very little dielectric effect at lower frequencies, exhibits an enormously enhanced loss at submillimetre frequencies.