Impact of different polyethylene glycol wood treatments on the adhesive properties of beech wood

ABSTRACT Modified beech wood, treated with polyethylene glycol (PEG), was examined regarding its adhesive properties. Therefore, beech wood was modified with various molecular weights and amounts of PEG. All variants of the PEG treatment lead to an improved dimensional stability of beech wood samples. Afterwards, three different kinds of adhesive systems were tested on the modified wood. The three adhesive systems were based on phenol-resorcin-formaldehyde (PRF), emulsion-polymer-isocyanate (EPI) and melamine-urea-formaldehyde (MUF). The adhesives were tested according to a delamination test between layers (DIN EN 16351 annex A) and a determination of the longitudinal tensile bonding strength (DIN EN 302-1 A1). The achieved results showed an effective wood modification with suitable bonding properties. The usage of PEG-modified beech in constructive applications such as cross-laminated-timber (CLT) seems to be possible.