ACHIEVING EFFECTIVE SURFACE PROTECTION OF INFERIOR WOOD BY USE OF PLASMA

The use of wood raw materials of different qualities undoubtedly allows the development and production of wood products with greater added and a more efficient use of wood raw materials. From the point of view of sustainable and efficient use of natural resources, it is necessary to special attention to wood, which is considered inferior due to its poorer mechanical, visual and other properties and is often excluded from the production processes. Natural disasters in forest ecosystems in recent years have led to the predominance of wood from sanitary felling on the market, and another type of inferior wood raw material is wood that is already installed but has deteriorated. Finding new ways to use this type of wood raw material to manufacture products with the goal of transitioning to a circular economy is therefore inevitable. An important role in the production of wood products is played by the quality surface finishing process, in which the surfaces of the products are covered and thus protected with various coatings. The proposed project will develop and evaluate a new integrated technological process that will allow high-quality surface treatment of three types of inferior wood: Bark beetle spruce wood, beech wood with presence of red heartwood, and worn surface-finished wood. The newly developed and introduced technology will be the treatment of wood surfaces with non-thermal air plasma. The use of this technology, through the processes of activation and changing the properties of wood surfaces, will help to improve their compatibility with various coatings, thus improving the protection of inferior wood. The plasma treatment (PT) process will be first optimized in terms of the best possible wettability of wood surfaces with water and selected coatings. The process will also be evaluated from an energy efficiency perspective by monitoring power consumption. Morphological, chemical and physical changes caused by PT of wood surfaces will be determined. Studies using bark beetle spruce wood infected with blue stain fungi as an example will also demonstrate the antimicrobial potential of PT. The properties of surface systems will be characterized on coated wood samples using various standard and non-standard methods. A portion of the surface-treated samples will be exposed to one year of outdoor weathering, which will provide realistic data on the contribution of PT of surfaces to their properties. The project's work program is systematically divided into 5 subprojects (SP) covering all planned project activities to achieve the set objectives: 1. SP represents the production of a prototype device for the PT of wood surfaces in a configuration with a dielectric barrier discharge and the characterization of its operation, 2. SP advocates the use, evaluation and optimization of the developed PT process of inferior wood in terms of the modification of wood properties as well as the study of the possible use of plasma to inhibit the growth of blue stain fungi on wood surfaces, 3. SP provides PT of wood in order to achieve the best possible compatibility of the surfaces of different types of wood with the selected coatin considering the energy efficiency of the process, 4. SP includes the evaluation of the resistance and durability of each surface system on the considered inferior types of wood, 5. SP represent activities that will take place in parallel with the implementation of the other subprojects. The results of the project's research will primarily address several gaps in our knowledge about the properties of inferior wood. Through an innovative approach, the introduction of a PT process, I aim to achieve changes in the surface properties of inferior wood while replacing conventional and less environmentally friendly approaches for wood protection (biocides). The proposed project will demonstrate the extent to which the new type of surface treatment can help expand the possibilities of using inferior wood.