A innovative application of lactose cross-linked adhesive in plywood using hyperbranched network structure with high performance

The use of biomass as raw material to prepare green biomass-based resins for wood adhesives is an effective way to alleviate the oil resource crisis and environmental problems. However, the reported biomass-based adhesives suffer from poor mechanical properties and water resistance, limiting their application to some extent. It is therefore of great interest to investigate new synthetic methods for the preparation of biomass-based adhesives with good mechanical properties and water resistance. In this paper, in order to improve the mechanical properties of biomass-based adhesives, this can be achieved through chemical modification of biomass and hyperbranched network cross-linking strategies. A new biomass-based hyperbranched adhesive, L-PEI, was prepared by co-crosslinking lactose and PEI through air oxidation strategy. The molecular structure of L-PEI was determined using FTIR, 13C NMR, X-ray photoelectron spectroscopy, LC-MS, GPC and other characterisation methods. During the modification process, the addition of PEI leads to the formation of a super branched network structure between lactose and PEI, increasing the crosslinking density and serving as a water barrier. The results of the study show that L-PEI has good adhesive properties and water resistance. Wet shear strength is 1.13 MPa after 3 h in hot water at 63 degrees C and after soaking in boiling water for 3 h, it is 1.1 MPa. In summary, L-PEI is a green, easy to synthesize and high performance wood adhesive.