Green-synthesized copper oxide nanoparticles for enhanced durability and termite resistance of coconut wood

The rising global demand for timber continues to strain natural forest resources, underscoring the need for sustainable alternatives. Coconut wood is widely available but exhibits low natural durability, which limits its commercial utilization. Conventional chemical preservatives such as chromated copper borate (CCB) and copper chromium arsenate (CCA) enhance wood performance but impose significant environmental risks. This study explores the application of biosynthesized copper oxide nanoparticles (CuONPs), produced using leaf extracts of neem ( Azadirachta indica ), lantana ( Lantana camara ), senna ( Senna spectabilis ), and teak ( Tectona grandis ), as eco-friendly nanoprotectants for coconut wood. Successful synthesis of CuONPs was validated through ultraviolet-visible spectroscopy (UV-Vis), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) analyses. The nanoparticles were incorporated into medium-density coconut wood via a vacuum-pressure impregnation technique, and their retention and interaction with coconut wood structure were confirmed using FE-SEM, EDS, FTIR, and XRD. Performance evaluation showed that wood treated with CuONPs synthesized from teak extract exhibited the greatest enhancement in physical and durability characteristics, including improved dimensional stability, higher resistance to moisture uptake, and superior resistance against termite attack, with only 0.61% mass loss compared to 25.36% in untreated controls. Although UV exposure tests indicated minimal improvement in color stability, the overall findings highlight that green-engineered CuONPs present a viable, sustainable, and less hazardous alternative to traditional preservatives for improving coconut wood performance and expanding its utility as a renewable material.