Polystyrene is a clear, colorless thermosetting-type plastic. It is widely used as an insulating material in radio-frequency circuits and, to some extent, as a dielectric film in fixed capacitors. Dielectric constant, 2.4 to 2.9. Dielectric strength, 20 to 28 kV/mm.
See also, Phenolic Insulants, Phenol-formaldehyde Plastics, Phenolic Resin, Polystyrene Capacitor