Effect of Climatic Variations and Mechanical Stress on the Strength of Epoxy-Wood Joints

Abstract

The influence of changing climatic conditions was studied relative to strength parameters—tensile strength, modulus of elasticity, and internal cohesion—of joints between hardened epoxy casting resin and solid wood. Samples were exposed to various climatic conditions, including ageing simulation under normal conditions (25 °C, 30% humidity), and extreme conditions (50 °C, 90% humidity). The study also examined the impact of incorporating oak wood dust (0.05% by weight) as a bio-based additive into the epoxy matrix. Chemical resistance of the cured resin—with and without the additive—was evaluated using a modified Buchholz indentation test following exposure to a toluene–naphtha–ethanol solvent mixture. Moisture content was assessed. Alternating climatic conditions significantly impacted the strength parameters, with extreme temperatures and humidity levels reducing joint integrity. Mechanical stress further exacerbated this deterioration, underscoring the importance of environmental considerations in applying resin-wood composites. Furthermore, the addition of oak wood dust improved the chemical resistance of the epoxy resin, suggesting enhanced durability and interfacial bonding. Visual inspection of post-failure specimens revealed a higher prevalence of cohesive wood failures in oak, indicating superior bonding compared to meranti. These findings offer insights for appropriate use of epoxy–wood joints in furniture applications conditions.