Physical, mechanical, and surface properties of Oriental beech coated with bio-based epoxide nano-coatings after weathering

There are many harmful chemicals in the wood protection and coating industry. These substances adversely affect human health over time and cause many diseases such as respiratory tract, skin, or lung cancer over time. In this study, bio-based nano-coatings as a replacement of bisphenol-A (BPA) were prepared by both protecting the wood organically and trying to prevent applications that would adversely affect human health. This study was aimed to improve wood properties such as oven and air-dry densities and water absorption (WA) from physical properties, color, gloss, and roughness from surface properties after natural weathering, and compression strength parallel to the grain (CSPG) from mechanical properties by coating these materials on Oriental beech wood. New bio-based epoxide–amine (EP) coatings were preferred over BPA material and their nano-composite coating derivatives including fullerenes, graphene, and carbon nanotubes were prepared by reactions of epoxy-functionalized tung. A diamine hardener (isophorone diamine) and epoxide tung oil (ETO) doped with nanoparticles were cured, and their physical properties were also determined. Consistent with our previous work, glycidyl methacrylate and tung oil were preferred to form epoxy-functionalized tung oil (ETO) by opting for a Diels–Alder reaction. The new bio-based epoxide–amine-cured systems were created at ambient temperature using a 1:1 epoxy-to-amine molar ratio. The specimens covered with epoxide nano-composites exhibited greater water resistance than the control group. When the surface properties of the epoxy nano-composite-coated specimens after weathering were examined, a more stable color change was observed compared to the control group. Furthermore, while the glossiness of the epoxide nano-composite-coated specimens decreased more than the control group, their roughness increased more. CSPG of epoxy-coated specimens increased a little bit compared to the control group, but no statistical difference was found.