Influence of Nanoclay on Phenol-Formaldehyde and Phenol-Urea-Formaldehyde Resins for Wood Adhesives

The addition of small percentages of Na+-montmorillonite (NaMMT) nanoclay does not appear to improve much the performance of thermosetting phenol-formaldehyde (PF) and phenol-urea-formaldehyde (PUF) resins used as adhesives for plywood and for wood particleboard. X-ray diffraction (XRD) studies indicated that NaMMT does not become completely exfoliated when mixed in small proportions to PF resins, contrary to that observed for acid-setting urea-formaldehyde (UF) resins. Differential scanning calorimetry (DSC) indicated that NaMMT has no accelerating effect on the curing of alkaline PF resins, contrary to that observed for UF resins.