Probing the Epoxy Insulation of Smoothing Reactors With Graphene Ink

Electrically conductive inks (ECIs) are up to now a growing research field, to create flexible circuits for power engineering. As a result, research into screen printing of conductive electrodes onto fiberglass-epoxy-reinforced laminates (FGERLs) has emerged. In this study, an ECI based on reduced graphene oxide (rGO) is proposed for screen printing of conductive electrodes on FGERL used in insulation of the high-voltage direct current smoothing reactors (HVDCSRs). The electrically conductive reduced graphene oxide ink (ECrGOI) was fabricated by mixing rGO, hyperbranched polyglycerol (HPGL) as an adhesion promoter, and poly (vinyl alcohol) (PVA) as a binding agent. The ECrGOI electrodes exhibited adhesion strength of 3.7 ± 0.3 N/mm2 and conductivity of
$1.2.10^{\text {-4}}$
S/cm at percolation threshold starting at less than 7.5 wt.% of rGO. The thermogravimetric analysis (TGA) indicates that ECrGOI exhibited good thermal stability at 400 °C. The attractive electric, thermal, and adhesive properties, combined with the ease of preparation and solution-processing capability, indicate that ECrGOI may have great potential applications in analysis of insulation produced by FGERL used in encapsulation of smoothing reactors.