• CAPILLARY PENETRATION (SPREADING AND WICKING) MECHANISMS IN PLASMA-AIDED SURFACE FINISHING PROCESSES

    Machines. Technologies. Materials., Vol. 10 (2016), Issue 1, pg(s) 53-56

    The plasma-aided flame retardation of wood, wooden products and cellulosic fibrous materials has been conceived and developed as a surface finishing process of capillary impregnation with nitrogen- and phosphorous flame retardant containing water solution. The surface pre-treatment in atmospheric pressure dielectric barrier discharge plasma substantially alters its capillary activity – the spreading on the wood surface and the wicking in the depth of wood, thus improving some basic characteristics of the impregnation process. This study has been developed as part of a large investigation on plasma-chemically activated (polarized, functionalized) wood surface and surfactants enhanced plasma aided capillary impregnation with nitrogen- and phosphor flame retardant containing water solution. The experimental studies of capillary activity changes on European white pine (Pinus Sylvestris, Bulgaria) wood surfaces using selected surfactants and spreaders show that they have substantial contribution to the effective plasma-aided capillary activity and impregnation processes.

  • WOOD SURFACE ENERGY DETERMINED BY SESSILE DROP TECHNIQUE AS QUALITY PARAMETER OF PLASMA-CHEMICAL MODIFYED WOOD SURFACES

    Machines. Technologies. Materials., Vol. 8 (2014), Issue 10, pg(s) 50-2

    The analysis of pre-treated wood surfaces, which have been plasma modified is also very informative for wood quality. Our measuring instruments determine the wettability based on the contact angle. The optical shape analysis of drops which are dispensed onto the surface is a reliable method for carrying out this measurement. The aim of this study was to verify possibility of determining the contact angle values of the plasma activated wood and calculate the surface free energy and its components of wood from the obtained contact angle values using Zisman, Equation of state (EOS), Fowkes and Wu theory and calculation method. Based on the contact angle data, the surface energy was obtained from the polar-dispersive(non-polar) approach. This study has been created as part of a large investigation on plasma- chemically activated wood surface and flame retardant treated wood.