Preparation of polymeric materials with semiconductor properties

Abstract

Abstract Thermal treatment of polyacrylonitrile synthesized by means of ionic polymerization, radiation polymerization, or redox initiation yielded substances giving signals in the EPR spectrum and possessing semiconductor properties. From the temperature dependence of the electroconductivity the activation energy was determined, and from the data on the EPR spectra the number of unpaired electrons (10 18 –5 × 10 19 /g.) was calculated. The thermoelectromotive force was determined and the existence of a Hall effect established. Addition of copper, iron, and chromium ions to the initial polymer lowers the activation energy and increases the width of the EPR signal. On dehydrobromination of natural rubber bromides and dehydrochlorination of polyvinyl chloride, conjugated double bond polymers were obtained, and their electrical properties were determined. Semiconductor properties were found in condensation products of phthalic anhydride with hydroquinone and the activation energy of these compounds was determined.