Investigation of a new resin as an exterior adhesive to bond high moisture content veneers and glulam

A new carbohydrate-phenol-based resin was synthesized by grafting resorcinol onto a known glucose-urea-phenol-based resole. Fast-curing adhesives formulated from this resin were evaluated by preparing 3-ply plywood specimens under hot-pressing conditions with veneers at 18 percent moisture content (MC). A preliminary investigation was also made on the use of this resin in a cold-setting adhesive formulation for glulam. Plywood specimens sheared dry and after vacuum-pressure treatment achieved an average 85-percent or better wood failure, but specimens sheared wet after a boil-cycle treatment averaged only 75-percent wood failure. Average wood-failure values were above 90 percent for all shear tests of glulam specimens. Microscopic analysis of plywood gluelines indicated some adhesive over-penetration and severe tracheid compression. Further research is needed, but these results demonstrate the potential for modifying carbohydrate-based resins to produce more versatile resins.

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member