Impregnation and bonding of hybrid wood-based materials in automotive body shell

The behaviour of wood-metal composites was evaluated during cathodic dip coating, which is a standard corrosion protection process for metals in automotive engineering. In this process, the materials are exposed to chemical and thermal stresses, which is a challenge for wood and composites based thereon, especially in terms of the durability of the adhesive and the differences in thermal expansion. In this study, a hydrophobic surface sealant was proposed to mitigate these negative effects by reducing moisture absorption during dipping baths. The mechanical properties, including flexural strength, tensile strength and impact strength of aluminium-plywood composites were evaluated. It was found that impregnation with low-viscosity resins improved the mechanical properties by increasing the bulk density of the wood. Although the dip coating process reduced the strength of the impregnated samples, they maintained higher values compared to the non-impregnated samples. The dip coating process significantly reduced the tensile strength of the non-impregnated samples, while the impregnation protected the samples and maintained the tensile strength. It was concluded that hydrophobic surface sealing by impregnation is crucial for improving the mechanical properties of wood composites in automotive applications, as it reduces moisture absorption and maintains mechanical integrity during the dip coating process.