Dielectric behavior and resistivities of polyacrylonitrile and some pyrolyzates

Abstract

Abstract Dielectric losses in polyacrylonitrile (PAN) and three pyrolyzates were studied between 1 Hz. and 300 kHz. Pure PAN has at 20°C. a very broad loss region with a maximum at 70 Hz. which is ascribed to CN groups. Powdered PAN was pyrolyzed in a nitrogen atmosphere at 170, 220, and 300°C. PAN‐170 has the same loss maximum as the unpyrolyzed polymer, but the maximum had disappeared in PAN‐220. This is attributed to formation of conjugated chains by linking of CN groups above 200°C. However, this does not enhance the conductivity until hydrogen is eliminated above 350°C.