Dielectric properties of polystyrene/onion-like carbon composites in frequency range of 0.5–500 kHz

Composites of polystyrene and onion-like carbon (OLC), produced from detonation nanodiamonds (NDs), have been fabricated by forge-rolling method. Optical microscopy and optical absorption spectroscopy were used for control of dispersion of OLC in polymer matrix after repeating rolling cycles. The impedance measurements of composites with different filler loading indicated the percolation threshold at ∼20–25 wt.% OLC concentration. The permittivity of the polystyrene/OLC composites varies from 2 to 10 with changing the OLC loading from 5 to 35 wt.%. Fitting the experimental data with model based on the Maxwell–Garnett approximation lead to conclusion that the shear deformation applied under the composite preparing disintegrates OLC agglomerates to the size ∼40–50 nm equal to the medium size of OLC in dimethylformamide slurry.