Adhesive Groups and How They Relate to the Durability of Bonded Wood

There is a need to develop models that evaluate the interaction of wood adhesives at the macroscopic level to explain observations on the durability of bonded wood laminate products with changing moisture conditions. This paper emphasizes a model that relates durability to strain on the bondline caused by wood swelling. The effect of this strain is discussed in relation to two groups of adhesives with different chemistry, structure-property and adhesive-wood interaction relationship models. The in situ polymerized adhesive group involves highly cross-linked polymers with a rigid backbone that need to limit the swelling of the wood surface to provide a durable bond. The pre-polymerized adhesive group includes polymers with backbone flexibility and limited cross-linking so that they can thus distribute the swelling strain within the adhesive. These models emphasize the importance of the adhesive-wood interactions and end-use application for establishing the performance criteria. (C) Koninklijke Brill NV, Leiden, 2009