Dielectric relaxation of fullerene C₆₀-containing nanocomposites based on poly(phenylene oxide)

Molecular mobility of nanocomposites based on poly(phenylene oxide) (PPO) containing 1, 2, 4 and 8 wt% of C₆₀ fullerenes was studied by dielectric spectroscopy. In all samples, two relaxation processes were present and caused by polarization of the single polar –O– group located between phenyl rings. This polarization includes two stages with the first stage (occurring in the glassy state) is caused by rotation of phenyl rings and the adjacent polar –O– groups by small angles that results in the local β process. The second stage (occurring at temperatures exceeding the glass transition temperature T_g) involves segmental mobility and leads to emergence of the α process. Molecular mobility in the region of the β process varies slightly with C₆₀ concentration. In the case of the α process, molecular mobility changes non-monotonically with increasing fullerene concentration.