The utilisation of turpentine and moss oil as epoxy hardeners for bio-based epoxy nanocomposite coatings

Abstract

Despite the growing interest in bio-based epoxy systems, there remains a significant research gap in developing fully bio-derived curing agents that can replace conventional BPA-based epoxy hardeners while maintaining adequate mechanical and physical performance on wood substrates. The objective of this study was to investigate the potential of new bio-based, bisphenol A-free epoxide nanocomposite coatings for wood surfaces, as a replacement for commercially available coating containing bisphenol A. In addition, the surface properties of these coatings were evaluated. This study involves the use of environmentally friendly, bisphenol A-free, new bio-based epoxy coatings and their nanocomposite derivatives, in which both the resin and hardener are derived from natural sources. The study is original in its use of sustainable natural resources in the coatings industry, as well as in the development of cost effective and readily available systems compared to those derived from petroleum. Futhermore, this he research is is the first to employ moss oil and turpentine oil as hardeners in epoxy resin curing reactions. The results obtained with these two oils, which share a similar chemical structure, were compared. The study also investigates the effect of nanoparticles on the physical and mechanical properties of the bio-based coatings. In this study, novel bio-based epoxide nanocomposite coatings for wood surfaces were prepared using a tung oil-based epoxide resin, which was cured with moss and turpentine oil for the first time. Moss oil and turpentine oil were utilised as epoxy hardeners. The wood species selected for this investigation was Fagus orientalis (oriental beech). Furthermore, as prospective substitutes for bisphenol A, the characteristics of the new bio-based epoxide coatings, specifically the system obtained using moss oil and turpentine oil as hardening agent, were evaluated in relation to their nanocomposite derivatives doped with carbon nanoparticles (fullerene, carbon nanotubes, and graphene) for application on wooden substrates. Following the application of various coating materials to the wood surface, evaluations were conducted on the mechanical and physical properties of the wood. This included measurements of water absorption, t oven-dry density, and compression strength parallel to the grain of Fagus orientalis (oriental beech). The findings revealed that all test specimens showed oven-dry density values higher than those recorded for the control group. After the final absorption period, all coated specimens demonstrated a reduction in water absorption compared to the control.. Each coated specimen also exhibited a higher compression strength parallel to the grain than the control group. Consequently, it was established that the implementation of innovative bio-based nanocoatings has the potential to enhance the mechanical and physical properties of Fagus orientalis (oriental beech) wood.