Preliminary studies for use of dynamic mechanical analysis (DMA) to verify intensity of thermal wood modifications

Colour change and/or mass loss due to thermal treatment are in direct relation to the performance of thermally modified wood. The application of techniques commonly used to characterise polymers may be used to study this relationship. A standard testing procedure in the field of plastics for the characterisation of bulk properties that directly affect material performance, is dynamic mechanical analysis (DMA). DMA indicates how a material will perform in a specific application. It can be used to identify the intensity of a thermal modification by evaluation of the viscoelastic response of wood. The paper presents the method together with results of preliminary tests with Norway spruce [Picea abies (L.) Karst.] and beech (Fagus sylvatica L.). The tests showed that it is possible to thermally modify small wood specimens directly inside the DMA equipment while, at the same time, getting real time mechanical and physicochemical information about the progress of the process.