Preparation And Characterization Research Of Crosslinking Modification Of Soy Protein-based Adhesive

In recent years,formaldehyde-based adhesives are widely substituted by soy protein based adhesive.To improve the water resistance and expend the application of soy protein based adhesive in wood industry,soy protein and soy protein isolate as the raw materials,1,4-Butanediol diglycidyl ether(BDDE)and lacquer as the cross-linker were used to prepare bio-based adhesive.The properties of the modified adhesives were examined by Thermogravimetric analysis(TGA),Fourier transform infrared spectrometer(FTIR)and Scanning electron microscope(SEM),and to explore the strengthening mechanism of modified soy protein based adhesive.The main conclusions were summarized as follow:1.1,4-Butanediol diglycidyl ether(BDDE)could improve the water resistance of the modified soybean-based adhesive,it is a long chain of epoxy compounds,BDDE effectively reacts with soy protein to form a dense network,thus enhancing the water resistance of the adhesive.In addition,BDDE has an ability of reducing adhesive viscosity,which benefits for the forming of adhesive bonding interface.When 8%of BDDE was added,the wet shear of plywood increased by 417%to 1.19MPa,which met the interior-use plywood requirements.2.Lacquer modified soy protein to prepare bio-adhesive,and effectively improve the water resistance of the modified adhesive.The urushiol can be oxidized to two benzene quinone in under certain conditions,which could cross-linked with soybean protein molecules,increasing crosslinking density of the modified adhesive.When the lacquer addition was 4%,and adding 1%NaClO,the wet shear strength of plywood increased by 242%to 1.06 MPa,which met the interior use plywood requirement.