Partial Substitution of Phenol in Phenol-Formaldehyde (PF) Resin By Plant Biomass for Wood Adhesives

The modified phenol-formaldehyde resin was synthesized by substituting the significant component of the resin by plant biomass. This research is bifurcated into three parts. The first part of this study was performed to understand the structure of plant biomass used by various characterization techniques like FTIR, ¹H-NMR, ¹³C-NMR, ³¹P-NMR, Py-GCMS, GPC and solubility. In the second part of the research, PF (novolac) resins were produced by polycondensation reaction between phenol and formaldehyde under an acidic condition with formaldehyde (F) to phenol (P) ratio less than. The bio-PF resin was synthesized by replacing 50wt% of phenol by kraft lignin, lignocellulosic bio-oil and lignin bio-oil to produce 50% PF resin of lignin, 50% PF resin of lignocellulosic bio-oil and 50% PF resin of lignin bio-oil respectively. These PF resins show the linear or partially cross-linked structure, and the addition of curing agent makes them formed a fully cross-linked network. The behaviour of the physical mixture of HMTA curing agent with PF resins was studied using DSC (differential scanning calorimetry) analysis. The result obtained from DSC analysis was for bonding wood laminate in a pressing machine. In the later part of the research, the wood laminate was bonded using each prepared PF resins, and their physical mixture with 9% HMTA curing agent and the properties like tensile shear strength wet and dry condition, water absorption and thickness swelling were measured.