Pretreatment using diluted epoxy adhesive resin solution for improving bond strength between steel and wood surfaces

Interfacial bonding strength is critical to key structural functions in the laminar composite of different substrates bonded together by adhesives. This paper reports a study on utilization of the micro-porous composite structures of a hard-Australian jarrah wood to enhance the adhesive bonding with steel substrates. The thin adhesive joint between the two different substrates is rooted deeply into the micro-channels within the micro-porous composite structures of the jarrah wood using a unique resin pre-coating (RPC) technique. The mechanical abrasion of the substrates was carried out before RPC. Based on single lap shear tests, over 180% of improvement in shear strength was achieved after optimizing the concentration of RPC solution. One important observation was the wettability of substrates was enhanced by RPC as well. A non-destructive technique, X-ray tomography, was employed to reveal the microstructural details of jarrah wood, confirming the usefulness and effectiveness of RPC.