COMPLEX PERMITTIVITY OF A FILM OF POLY [4-(ACRYLOXY)PHENYL(4-CHLOROPHENYL)METHANONE] CONTAINING FREE-ION IMPURITIES AND THE SEPARATION OF THE CONTRIBUTIONS FROM INTERFACIAL POLARIZATION, MAXWELL-WAGNER-SILLARSEFFECTS AND DIELECTRIC RELAXATIONS OF THE POLYMER-CHAINS

The previous theoretical study of measured complex permittivities of t he amorphous copolymer of vinylidene cyanide and vinyl acetate (T. S. Sorensen and V. Compan, J Chem. Soc., Faraday Trans., 1995, 91, 4235) is refined and used to explain measurements of the complex permittivit y of the amorphous polymer poly[4-(acryloxy)phenyl(4-chlorophenyl)meth anone] at different temperatures and frequencies. Throughout the paper we stress the use of physical models rather than the traditional use of equivalent circuits without much informational content. The data ex hibit a maximum in the loss tangent at low frequencies (below 0.1 Hz) which can be explained by interfacial polarization near the two conden ser plates, and from which information concerning the diffusion and th e concentration of free charge (mobile ion) carriers may be estimated. The diffusion coefficient for the fast ion varies from 1.9 x 10(-14) m(2) s(-1) at 120 degrees C to 1.8 x 10(-13) m(2) s(-1) at 140 degrees C. The activation energy for diffusion is E(a)/R approximate to 12 80 0 K. At frequencies in the range 0.1-10 Hz, the Maxwell-Wagner-Sillars contribution dominates. This contribution is due to the bulk conducti vity of the free charge carriers. From the value of this conductivity and the information obtained from the interfacial polarization, the va lue of the static permittivity of the polymer may be found. Experiment ally, this value is completely obscured by the effects of the free cha rge carriers. At higher frequencies, the dielectric relaxations connec ted with the motion of segments of the polymer chains are seen if corr ections are made for conductivity. Two dielectric loss peaks are obser ved moving towards higher frequencies when the temperature increases. The low frequency relaxation has an activation energy E(a)/R approxima te to 11 200 K. For the high frequency relaxation E(a)/R approximate t o 24 500 K. The approximate identity of the activation energy of the l ow frequency relaxation and the activation energy of diffusion might i ndicate that the same molecular reorientation is involved in both case s.