Physico-mechanical properties of resol phenolic adhesives derived from liquefaction of oil palm empty fruit bunch fibres

Utilization of oil palm empty fruit bunch (EFB) fibres in the production of phenolic (PF) resin is an alternative way to reduce the dependency of petroleum-based phenol. In this study, resol-type phenolic resin was synthesized from oil palm EFB fibres via liquefaction process using phenol and sulfuric acid, followed by resinification reaction with formaldehyde in alkaline condition. The increase of the ratio of formaldehyde/liquefied EFB (F/LEFB) results in the increase in the viscosity and molecular weight of the produced PF resin. The obtained FTIR spectra confirmed that the chemical functionalities of the produced PF resin are almost similar to that of commercial PF resin. The NMR analyses indicated that the phenol para position was favoured for the reaction over the ortho position in both commercial resin and resin synthesized due to the existence of steric hindrance effect from the hydroxyl phenol and phenol derivatives of liquefied EFB. The shear strength of the produced PF resins is fulfilling the requirement as specified in JIS K-6852.