Preparation and Characterization of a Phenol-formaldehyde Resin Adhesive Obtained from Bio-ethanol Production Residue

Abstract

Enzymatic hydrolysis (EH) lignin was utilized to replace phenol partially for preparing phenol-formaldehyde (PF) resin adhesives. The influence of the degree of lignin substitution on the properties of the lignin phenol-formaldehyde (LPF) resin adhesive was investigated. The results demonstrated that up to 50% of phenol in the resin could be replaced by EH lignin without damaging the bonding strength of the adhesive, and a lower free phenol content was observed in LPF resin adhesives. Fourier transform infrared spectroscopy spectra of the resins revealed that the introduction of lignin did not appreciably change the final chemical structure of the adhesive, but did negatively impact the resin's thermal ultimate stability. Furthermore, compared to bio-ethanol production residue-modified phenol-formaldehyde (ERPF) resin, the LPF resin exhibited higher bonding strength at the same level of the phenol substitution. This result of the comparison indicated that the raw biomass extraction process improved the performance of the bio-based PF resin.