Phenol-formaldehyde resin enriched with graphene nanoplatelets as an electroconductive adhesive for wood composites

Abstract

The study demonstrates that phenol-formaldehyde (PF) resin, commonly used for lignocellulosic composites, can become electroconductive when modified with graphene nanoplatelets (GNPs) while still serving as an effective adhesive for particleboard production. The PF resins enriched with various amounts of GNPs were tested for viscosity, gel time, and thermal stability, followed by electrical conductivity measurements for GNP-enriched resins applied to several lignocellulosic surfaces of varying wettability. These tests showed that the optimum weight percentages of GNP at which the resins maintain both the electrical conductivity and process parameters, enabling the formation of particleboard, amount to 18.5%. Consequently, a prototype of electroconductive particleboard was created and evaluated for bending strength (EN 310: 1993), modulus of elasticity (EN 310: 1993), tensile strength (EN 319: 1993), thickness swelling (EN 317: 1993), water adsorption (PN-76/D-04234) and formaldehyde emission (EN ISO 12460–5:2015). Impressively, the panels achieved a conductivity of 320 Ω m, indicating their potential use as resistive heaters and other applications in the Internet of Things (IoT) area. Simultaneously, the GNP-enriched panels showed formaldehyde emission well below the threshold set by the standards and exhibited mechanical properties that in most cases met the criteria for use in furniture and interior design.