The Dielectric Properties of Cyanoethylated Polyvinyl Alcohol

Abstract

Polyvinyl alcohol was reacted with acrylonitrile (i.e., cyanoethylated) to obtain a series of polymers differing in degree of cyanoethylation . Dielectric constants (ε′) and of these cyanoethylated polyvinyl alcohols were measured from 60 cps to 300 kcps and −50° to 75°C; d‐c volume resistivities (ρ) were measured at 25°C. Unusually high dielectric constants were observed; however, the losses did not develop dispersion peaks within the frequency range studied even on cooling the polymers to −50°C. In general, ε′ and first decreased slightly with increasing cyanoethylation, then increased and reached plateaus or maxima at 30 to 40% Cross linking the polymer had little effect on dielectric properties when the was high, but lowered ε′ and ε″ and increased ρ when the was low; these changes were greatest with unmodified polyvinyl alcohol . Polar group substitution presumably accounts for the observed variations in dielectric properties.