Improving the mechanical properties of wood by melamine-formaldehyde impregnation of cell walls

While sufficiently strong and stiff in longitudinal direction, wood is rather weak in the direction normal to the grain. This fact imposes some limitations on the suitability of wood for a variety of applications. Problems arise with hard wearing surfaces, in particular in flooring applications, where wood is losing market shares to MDF boards coated with sheets of melamine-impregnated papers mimicking the optical appearance of wood, and also where wood is exposed to large stresses normal to the grain, such as in joints in structural applications. In a preliminary study it could be demonstrated, that a melamine-formaldehyde resin is able to diffuse into the wood cell wall and that this provides a considerable reinforcement in compression. This effect is achieved without leaving lumina filled with melamine resin after treatment, solely by changing the material properties of the cell wall. Fundamental aspects of melamine reinforcement of wood, such as a study of the mechanism behind the reinforcement, and more application oriented aspects such as reduction of brittleness of the composite, effects of varying moisture content, fatigue behaviour and optimum thickness of the reinforced layer to resist indentation will be investigated in the proposed project, combining mechanical testing with light microscopy, SEM, and TEM.