Novel hyperbranched resin for wood adhesive: Based on air oxidation and crosslinking copolymerization strategy

At present, environmentally friendly high-performance wood adhesives have received widespread attention. Glucose and tris(2-aminoethyl)amine (TAEA) were used as raw materials in this study. In the absence of catalysts, glucose-based wood adhesives with the hyperbranched crosslinking structure were prepared by the one-pot based on air oxidation and crosslinking copolymerization. The structures of the polymers were characterized by FT-IR, 13C NMR, LC-MS, and XPS. The results indicated that the interaction between glucose and TAEA is achieved through the dehydration reaction of carboxylic acid and primary amine, as well as the esterification reaction of carboxylic acid and alcohol. The hyperbranched polymer resin (GT) was successfully synthesized and used as a wood adhesive. The curing and thermal stability of GT adhesive were studied by DSC and TGA, and the results showed that GT had good thermal stability. The best-performing GT adhesive was screened by changing the molar ratio of tris(2-aminoethyl)amine/glucose and reaction time using the controlled variable method. The prepared GT adhesive has reached the national standard GB/T 17657-2013 (≥0.7 MPa) through the test of adhesive strength and water resistance. The dry shear strength of the plywood reached 1.97 MPa, and the strengths were 1.64 MPa and 1.31 MPa after immersion in hot and boiling water for 3 h. The experimental process is simple and green and the prepared hyperbranched glucose-based adhesive has excellent performance. Therefore, it has potential application prospects as a formaldehyde-free wood adhesive.