Effect of the Carbon C₆₀, C₇₀ Contents on the Dielectric Properties of Polyimide Films

摘要

The paper presents results of dielectric measurements of polyimide films with C₆₀ and C₇₀ fullerenes added in various ratios. Changes of capacitance and dielectric losses were measured in frequency range 10²-10⁶ Hz, at the temperature of 300K. Relaxation analysis was based on Havriliak-Negami equation. Influence of type and amount of fullerene in samples on dielectric properties was observed. Even its minimal amount (0,05%) increases capacitance from 10 to 20% - depending on type of fullerene. Dielectric losses coefficient is decreasing while C₆₀ and C₇₀ carbon contents is increasing. Approximation of dielectric spectra with Havriliak-Negami equation allowed to estimate changes of time constants of β-relaxation process. Modification of polyimid with carbon C₇₀-type has no significant influence on time constants, while increasing amount of carbon C₆₀-type leads to shorter β-relaxation times.