A self-adhesive bark veneer for all-natural plywood

The commercial plywood is mainly made of high-value wood veneer and formaldehyde-based adhesives, which pose a major risk to human health and environmental protection. Here, we report an all-natural plywood made of self-adhesive bark veneer directly from hardy rubber trees (HRT) via delignification, epoxidation reaction and densification. The resulting bark veneer is demonstrated with sandwich structures featuring natural integration between cellulose and biopolymer Eucommia ulmoides gum (EUG). The intrinsic EUG act as a potential strong "self-adhesive" and water-proofing agent, leading to bark veneer with high hardness, excellent hydrophobicity, wear resistance, and low thermal conductivity. Furthermore, we can produce the self-adhesive plywood on a large scale directly from HRT bark using this approach without any adhesives, endowing it with environmental friendliness, safety in use, and health benefits of human beings. Combining its efficient and low-cost production, the bark veneer shows great promise in fabricating high-performance and environmentally sustainable plywood.