PHENOLIC RESIN WOOD INTERACTION

A series of phenol-formaldehyde resole resins was made with varying formaldehyde-to-phenol molar ratios (1.70, 2.00, and 2.30) and sodium hydroxide-to-phenol molar ratios (0.40 and 0.60). Abroad molecular weight range from each type of formulation was characterized for viscosity, density, molecular weight, surface tension, and contact angle. Resin surface properties, wood wetting, and wood surface property alterations were examined with reference to the resin formulations and resin characteristics. The study found that the surface tension of phenol-formaldehyde resole resins varied with sodium hydroxide level, formaldehyde level, and molecular weight. Capillary forces affected the wood wetting mechanism. Work of adhesion on Plexiglas(R) decreased with increasing resin molecular weight. Wood wetting could be inhibited or enhanced depending on wood surface treatments.