Investigation into Adhesion of Coatings and Adhesives of Eucalyptus and Grey Poplar for Building Applications

This study investigated the bonding strength and chemical composition (as an influencing factor of adhesion) of red eucalyptus (Eucalyptus camaldulensis) (EUW) and grey poplar (Populus canescens) (GPOW) wood surfaces, comparing their suitability for indoor and outdoor wood-building applications. The research focused on adhesion strength using different coatings and adhesives, including lasure and 2K lacquer. The results showed that whilst both wood species had a conveniently high cellulose content, GPOW had a higher cellulose content (48.21%) than EUW (45.18%). However, EUW demonstrated superiority in tensile shear strength tests when using structural adhesives. Additionally, EUW exhibited stronger pull-off adhesion with 2K lacquer (5.25 MPa) compared with GPOW (3.42 MPa), suggesting that whilst both reached the expectations, EUW was more appropriate for high-stress indoor applications like flooring or wall cladding. EUW and GPOW performed well with lasure, achieving comparable adhesion strengths. EUW had a density of 1020 kg/m3 vs. 575 kg/m3 for GPOW and stronger bonding capabilities than GPOW, which suggests that it is equally suitable for wood applications inside and outside buildings. The study concluded that whilst both wood species met expectations and proved to be suitable for doors, windows, and other wood-building product applications, GPOW was suitable for the production of cellulose-based products, while EUW was worth relying on for its excellent adhesion to coatings and adhesives.