Preparation of phenol-formaldehyde resin modified with phenol-rich pine needle pyrolysis oil and assessment of bonding strength

Abstract

ABSTRACT The pine needles bio-oil was partially replaced with phenol-formaldehyde (PF) resin at a rate of up to 40% by weight. The wood adhesive characteristics of a newly produced bio-oil phenol-formaldehyde (BOPF) resin with 10% bio-oil replacements was found to be comparable to those of pure PF resin with similar shear strength. DSC revealed that the curing temperature of 20 wt-% BOPF resin decreased from 95 to 60°C. Thermal degradation of BOPF resins was somewhat lower than that of pure PF resin, according to TGA and DTG data, and was similar in 10 and 20 wt-% BOPF resins. The presence of methylene bridges between phenols shown by FTIR analysis indicated that the wood adhesive had a good quality. According to SEM examination, the 10 and 20% BOPF resins showed a flat microstructure comparable to the pure PF resin.