Analysis of Electrical Conductivity in Commercial Adhesives Incorporating Graphene Nanoplatelets for Industrial Applications

Polymers are often insulators, but this not a universal intrinsic characteristic of all polymers. For this work, the adhesives used, epoxy and polyurethane, do demonstrate this insulating characteristic. However, there has been significant interest in the development of conductive polymers, specifically adhesives, because of the potential properties and ease of processing of these polymers. The electrical-conductivity values for two composites reinforced with graphene nanoplatelets (GNPs) were measured. Both matrices are intended for industrial usage. One composite used an epoxy matrix, while the other employed a polyurethane resin as the matrix. To achieve dispersion and exfoliation of the filler, the catalyst for each resin, mixed with the GNP in proportion, was subjected to an ultrasonic bath for 30 min. The molds were filled by gravity, with the polyurethane specimens leveled to improve surface finish. The two-point uniaxial method was used to measure the conductivity of the specimens at room temperature, both before and after annealing at 120 °C for 120 min. Conductivity values were obtained for all samples, showing an increase after annealing; however, this increase was less pronounced compared to similar studies. The time and power in the ultrasonic bath, as well as the annealing conditions, must be optimized and the electrical conductivity should be studied periodically.