Permanent polarization in poly(acrylonitrile)

The dielectric behavior of poly(acrylonitrile) (PAN) has been investigated through the formation of electrically polarized films. The formation of films having a persistent electrical polarization has been achieved by the application of electric fields of the order 104 V cm−1 at temperatures ranging from 130 to 160 °C. The thermally stimulated discharge spectrum of PAN reveals at least three different peaks, two of which might be related to the relaxation of oriented nitrile side groups (90 and 145 °C). Intense current peaks observed above 160 °C are believed to be associated with backbone mobility in amorphous and paracrystalline regions. It is suggested that nitrile orientation with an applied electric field results in the formation of a highly developed level of intermolecular bonding.