(659f) Wood Adhesive As a Coproduct of Cellulosic Alcohol: Crosslinking and Bond Performance

The conversion of woody biomass to fermentable sugars through enzymatic saccharification (hydrolysis) often leaves behind solid residues that are rich in lignin. Our laboratory had demonstrated that these residues can be converted into a thermosetting wood adhesive without pre-purifying for lignin. This presentation reports the evolution of crosslinking during thermal curing of the adhesive. Aspen wood flour was enzymatically hydrolyzed, milled, and blended with a biobased crosslinker before application onto wood sticks to form lap shear specimens. The lap shear assemblies were hot-pressed for different durations of time and then mechanically tested to infer bond strength development. Variously cured adhesives were also examined for characteristic functional groups of the crosslink using infrared spectroscopy and conductometric titration. Results showed that the amount of functional groups was closely correlated to the lap shear bond strength of the cured and partially cured adhesive. This finding suggests that the bond performance of the adhesive can be potentially optimized by manipulating crosslinking conditions during thermal curing. This outcome signifies an improved understanding of saccharification residues for adhesive coproducts aiming at increasing the economic viability of the bioenergy system.