Multifunctional wood composites based on Camellia oleifera shell with harsh‐weather and self‐mildew resistance

Abstract Camellia oleifera shell is rich in lignin and tea saponin and other natural active substances, and it is used to directly prepare fuel and biochar, which are low‐value applications. Inspired by the tea oil fruit shell, a new type of wood‐based composite was designed, which was bonded between inner layers and coated on the surface with Camellia oleifera shell‐based phenolic resin through a one‐step manufacturing process. The acid catalyst type, reaction time, and substitution ratios (Camellia oleifera shell/phenol) were used to optimize the formulation and process of Camellia oleifera shell phenolic resin. The chemical structure, wet bonding strength, harsh‐weather resistance, thermal properties, and flame resistance of the composites (Camellia oleifera shell phenolic resin surface coated plywood [CSPCPs]) were evaluated. The results indicated that the CSPCPs showed better‐wet bonding strength and thermal properties and harsh‐weather resistance compared with the common uncoated plywood. CSPCP‐3 presented the maximum wet bonding strength of 1.63 MPa. The limiting oxygen indexes of the CSPCPs were all higher than that of common plywood. All CSPCPs displayed excellent acid rain corrosion resistance, with little mass loss under simulated acid rain conditions. Grayscale was used to compare the samples' color to assess their self‐mildew resistance. As the amount of shell increased, the mold resistance of CSPCPs increased. CSPCP‐3 showed excellent comprehensive performance and can be a multifunctional wood composite suitable for outdoor applications.