Electronic and ionic conductivity in nylon 66

The conductivity of dry poly(hexamethylene adipamide) (nylon 66) was measured as a function of time and temperature. Three temperature ranges were observed in which the time dependence of conductivity differed: ( a ) below 80°C. the conductivity decreased continuously with time; ( b ) between 80°C. and 110°C. the conductivity remained constant over long periods; ( c ) above 120°C. a continuous decrease in conductivity was again observed. In other experiments the volume of gas evolved from the nylon film was measured under continuous potential and compared with the total current passed through the sample. It was observed that above 120°C. the gas evolved corresponded to about one‐half the volume calculated if the conduction process involved only protons. Below 120°C. the gas evolved corresponded to an increasingly small fraction of the total current until below 90°C. no evolution of gas was observed. This suggests that at temperatures above 120°C. conduction involves the transport of both protons and electrons, whereas at lower temperatures it is electronic. Mechanisms of conduction are discussed.