| 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. |
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