Viscoelastic and electrical properties of RGO reinforced phenol formaldehyde nanocomposites

Graphene oxide was reduced (RGO) by naturally abundant potato starch and incorporated in phenol formaldehyde resin (PF). The PF/RGO nanocomposites were successfully fabricated by the combination of solution processing and compression molding. Here, nanocomposites composed of 0.05 wt% to 1 wt% RGO were prepared. The incorporation of RGO into the PF matrix was significantly affecting the dynamic mechanical characteristics of the nanocomposites such as storage and loss modulus and tan δ. The degree of entanglement (N), effectiveness of filler (β_f), reinforcement efficiency factor (r), cross-link density (v_c), and adhesion factor (A) were evaluated from the modulus values. Besides, the phase behavior of the nanocomposites was analyzed with help of Cole–Cole plot. The electrical properties of the nanocomposites have been studied concerning change in filler loading and frequency. The dielectric constant (ε′), dielectric loss (ε″) and conductivity were increased with increase in wt% of filler for the entire range of frequencies (20 Hz to 30 MHz) and the results showed that the electrical conductivity of the nanocomposites can be explained by percolation theory. The Maxwell-Garnet model was employed to calculate the theoretical dielectric constant of PF/RGO nanocomposites.