Accelerated Aging Procedures for Glue-Wood Bonds and their use for In-Plant Quality Control

Bond degradation in a particulate material like waferboards or oriented strand boards bonded with synthetic adhesives like phenol formaldehyde or urea formaldehyde can be explained as a failure or the breaking of the three dimensional mechanical branching of the cured adhesive due to the stresses generated by shrinking and swelling of wood as a result of moisture changes, as well as due to the chemical degradation of the adhesive which is hydrolytic in nature. In a service environment, the principal factors causing glue-wood degradation are (1) heat, (2) moisture, (3) stresses (generated during shrinkage and swelling), (4) microorganisms, and (5) chemicals.