The study analysed the effect of modification of phenolic resin with alkylresorcinols and H2O2 on properties of softwood and hardwood plywood resinated with such modified PF resins. Conducted tests showed that the application of PF resin modified with alkylresorcinols makes it possible to manufacture plywood with improved properties, especially bond quality, than those of the control plywood pressed under identical conditions. In turn, the introduction of H2O2 both to pure PF resin and resin modified with alkylresorcinols improves properties of plywood as a result of enhanced reactivity and increased chemical adhesion of resin to wood. Moreover, applied PF resin modification methods make it possible to manufacture plywood with very good properties at pressing time reduced by 25%.
The study investigated the effect of the modification of phenolic resin with sodium oxalate and ethylene glycol on properties of particleboards. It results from the conducted tests that the simultaneous introduction of ethylene glycol and sodium oxalate to PF resin, irrespective of the amounts of modifiers, results in a slight increase in bend- ing strength and modulus of elasticity of particleboards. However, a strong decrease was observed in internal bond after the boiling test. Observed changes in properties of par- ticleboards, occurring under the influence of the applied modification, undermine the applicability of such a modification.