ADHESIVE PROPERTIES OF FURFURAL-MODIFIED PHENOL-FORMALDEHYDE RESINS AS ORIENTED STRANDBOARD BINDERS

Furfural-modified phenol-formaldehyde (PF) resol resins were synthesized by replacing the formaldehyde at a 12.5 mole% level with furfural. The nonvolatile solids contents were set at 42%, 46% and 50% to reflect the molecular weight range of the comparable PF resol resins currently used in this application. Evaluations of these furfural-modified PF resins as oriented strandboard (OSB) adhesive hinders indicated that the furfural modification at this level is a technically feasible method. The chemical structure of furfural-modified PF resins studied by fractionation and C-13 NMR has shown that furfural is incorporated within the phenolic polymer structure most likely as furanylmethine groups while some furanylmethylol groups are also present in low molecular weight fractions.