(152c) Synthesis of Biobased Phenol-Formaldehyde Wood Adhesives from Biorefinery Derived Lignocellulosic Biomass

The high utilization of adhesives in the wood industry and increasing use of petroleum-derived chemicals for their synthesis has enhanced the opportunities for lignocellulosic biorefineries to reduce environmental and energy crises. In this study, lignin received from kraft biorefinery, bio-oils obtained from solvent liquefaction, and fast pyrolysis, laboratory-scale thermochemical conversion processes have been thoroughly characterized by FTIR, 2D HSQC-NMR, and GCMS technique before utilizing them as a monomer in phenol-formaldehyde resin synthesis. To further understand the structure of PF (phenol-formaldehyde) resins, FTIR and ¹H-NMR analysis were performed. Additionally, the reaction of PF resin with hexamethylenetetramine curing agent favors the crosslinked structure, and this curing phenomenon was studied using differential scanning calorimetry (DSC), where every resin and curing blend shows a deep exotherm peak during the process. The adhesive performance of resins on the wood substrate was evaluated by shear bonding strength under both wet and dry conditions along with physical properties such as water absorption and swelling behavior. The result from the study shows that incorporating kraft lignin was able to improve the bonding strength of wood specimens.