Acrylamide macromolecules modified wine lees‐soy protein wood adhesive

To expand the diverse applications of wine lees and enhance the adhesive properties of its protein‐based adhesive, the supernatant of wine lees, separated using the alkali solubilization method, was combined with a small quantity of soybean protein as the raw material. Cross‐linking modification was then conducted using polyacrylamide polymers to prepare the protein‐based adhesive. The results indicated that a total mass fraction of 2.5 wt% NaOH and 3.0 wt% urea effectively stretched the protein structure. Additionally, a mass ratio of 4:10 of trimethylolpropane triglycidyl ether and acrylamide, under the action of the ammonium persulfate initiator, resulted in effective cross‐linking of polyacrylamide macromolecules. The addition of 7 wt% polyacrylamide macromolecules as a cross‐linking agent effectively facilitated the cross‐linking reaction with wine lees‐soy protein. After the cross‐linking modification, the surface of the adhesive became tight and smooth. As a result, the water‐resistance strength of the plywood increased from 0.2 to 1.27 MPa, marking a 635% enhancement, which significantly surpassed the standard for Class II plywood (GB/T 9846‐2015). Schematic diagram of the synthesis route and bonding mechanism of wine lees‐soybean protein‐based adhesive.