A Novel Formaldehyde-Free Adhesive from Jatropha Curcas Press-cake

Jatropha curcas (Jc) was the most favored biomass plant for bio-diesel production. Jc cakes obtained after oil pressed, rich in protein content, were excellent materials for preparing formaldehyde-free wood adhesives, which could provide alternative to formaldehyde-based resins. Sodium hydroxide, used as denaturing agent, modified protein contained in Jc cakes to prepare wood adhesives. Jc adhesives prepared in different pH value and plywood bonded by them were prepared. The curing behavior of these adhesives was conducted by differential scanning calorimetry (DSC) measurement. The gel content and water absorption of the cured Jc adhesives were measured to evaluate their curing content and the water resistant of plywood bonded with these adhesives was also studied. The results showed that pH value influenced the bonding strength of adhesive significantly. The bonding strength of plywood made by modified Jc adhesive significantly increased comparing with that of unmodified one. The curing peak temperature decreased obviously after modified, which was beneficial to achieve complete curing reaction. Modified Jc adhesives provided a potential way to utilize by-product of energy plant, avoided formaldehyde pollution, and reduced dependence on fossil resources.