Modification of the beech – wood surface by UV – irradiation

The paper presents research into the possibilities of the modification of the beech-wood surface by exposure to the electromagnetic waves in the UV spectral portion. The simultaneous action of moisture and high-intensity UV light causes changes of the beech-wood properties and its surface energy. Since these parameters are highly influential in the gluing mechanisms, the experiment has been performed with the scope of determining whether such exposure can lead to an increase in the glue-bond strength. The effect of UV light was assessed by measurements of the surface energy and the glue-bond strength of the exposed and control specimens. The test specimens were made according to the DIN EN 204 norm, the length of the specimens being reduced in order that the testing surface occupies the greater proportion of the surface of the assembled woodplates. The shear stress was induced by compression to the specimens. The results indicate that the UV irradiation prior to adhesive application can improve the strength of the bond. The continuation of this experiment will enable the determination of exact parameters of the method.