Engineering of material properties by adhesive selection at the example of a novel structural wood material

The present study focused on the influence of adhesive selection on the properties of a novel structural wood composite using three different adhesive systems, namely polyurethane (PUR), phenol formaldehyde (PF) and polymeric methylene diphenyl diisocyanate (pMDI). As raw material spruce wood was used, which was disintegrated to macroscopic wood fibres, by means of a recently developed non-cutting disintegration process. These macro-fibres are oriented along the naturally grown fibre direction within a tree, have a high aspect ratio and correspondingly excellent mechanical properties together with a favourable density to strength ratio. These macro-fibres represent a challenging new surface for adhesive bonding. Depending on adhesive type, macro-fibre wood composites could be produced within a wide range of density spanning from 200 to 1300 kg/m(3). Despite of adhesive type and corresponding process needed, density and the total amount of applied adhesive showed highest influence on mechanical and swelling behaviour.