Enhancing weatherability and mechanical properties of tung oil wood finishes through natural rubber modification via the Diels-Alder reaction

Tung oil is commonly utilized for coating protection in wooden products, often attracting attention for its appearance, antimicrobial capabilities, and insect-resistant coatings. However, its poor mechanical properties and poor weather resistance stem from excessive self-crosslinking of surplus conjugated double bonds and molecular chains, resulting in poor film wrinkling. Therefore, this study introduces natural rubber via the Diels-Alder reaction to consume the residual double bonds in tung oil, resulting in tung oil/natural rubber composite coatings (NRTO) with excellent mechanical properties and weather resistance. The results indicate that NRTO exhibits excellent mechanical properties, including high elongation (32 %) and strong adhesion (4.55 MPa). Furthermore, NRTO demonstrates outstanding acid resistance and UV aging resistance. Given its many benefits, NRTO film emerges as a promising candidate for substantially protecting wood surfaces in demanding environments.