Electrical properties of polymers modified by electron beam irradiation

The formation of electrically conductive polyene structures in electron-beam-irradiated poly(vinyl chloride) is investigated. Thin specimens are irradiated to a progressively increasing exposure and the chemical structure is characterized by Fourier-transform infra-red spectroscopy. The direct-current electrical conductivity is also measured. It is shown that short polyenes are formed, the structure being less ordered and containing more defects than polyacetylene. The conductivity changes with exposure follow initially an exponential function, related to the loss of chlorine, but at high exposures a decrease in conductivity is observed. At the peak, which for a 200 keV electron beam is at an exposure of 800 C m −2, the electrical conductivity will reach the level of undoped polyacetylene, i.e. 10 −5 S cm −1. The use of zinc chloride as an activator is investigated. It is shown that it not only accelerates the dehydrochlorination, but it also increases the ultimate conductivity to the level of 10 −2 S cm −1 at an exposure of 200 C m −2.