Reduction of Weathering Degradation of Wood Through Plasma-Polymer Coating

Abstract

A novel plasma-enhanced coating for wood substrates has been developed which diminishes the degradation of wood under simulated harsh environmental conditions. Reflective (zinc oxide) and electromagnetic radiation (EMR)-absorbent (benzotriazole, 2-hydroxybenzophenone, phtalocyanine, and graphite) substances were incorporated into a liquid phase, high-molecular-weight polydimethylsiloxane and deposited as thin layers on wood surfaces. The macromolecular films, containing the dispersed materials, were then converted into a three-dimensional solid state network by exposure to a 30 kHz-oxygen-RF-plasma. The discharge induced chemistry and altered surface topographies in the surface layers were monitored by survey and high resolution Electron Spectroscopy for Chemical Analysis, Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy, and Scanning Electron Microscopy. The surface characteristics and the resistance to weathering of the plasma treated substrates were evaluated and compared to the properties of un-modified samples. Keywords Southern yellow pine Weathering degradation Cold-plasma-induced surface modificationBrought to you by | University of Manchester Authenticated Download Date | 5/25/15 9:26 PM Fig. 22. Percent weight loss of PDMSO matrix coated wood samples ( 0: un-treated; 1: only PDMSO; 2: benzotriazole/PDMSO; 3: ZnO/PDMSO; 4:hydroxybenzophenone/PDMSO; 5: phthalocyanine/PDMSO; 6: graphite/PDMSO).Fig. 23. Water contact angle of reflective and EMR-containing PDMSO matrix, before and after simulated weathering test (solid bars represent data for un-weathered samples and hatched bars represent data for 2-week-weathered samples; 0: un-treated; 1: only PDMSO; 2: benzotriazole/PDMSO; 3: ZnO/PDMSO; 4:hydroxybenzophenone/PDMSO; 5: phthalocyanine /PDMSO; 6:graphite/ PDMSO). Brought to you by | University of Manchester Authenticated Download Date | 5/25/15 9:26 PM

Wettability of Hybrid Poplar Veneers with Cold Plasma Treatments in Relation to Drying Conditions

“…[27,28] Southern yellow pine wood surfaces were modified under cold plasma conditions by Denes et al [29] to create a hydrophobic surface with an increased contact angle. Denes and Young [30] also used plasma-polymer coating to reduce weathering degradation of wood. It was believed that a plasma-enhanced coating formed a macromolecular thin film with dispersed reflective materials (such as zinc oxide) and=or electromagnetic radiation-absorbent substances.…”

Surface modification of poplar veneer by means of radio frequency oxygen plasma (RF-OP) to improve interfacial adhesion with urea-formaldehyde resin

“…A variety of surface treatment techniques have been applied to modify veneer surfaces to reduce the resin application level (Rowell et al 1986;Uysal et al 2009;Wolkenhauer et al 2009). Plasma treatment is a high-tech method for wood surface modification to improve its adhesive bonding (Denes and Young 1999;Rehn et al 2003;Bente et al 2004;Blanchard et al 2009;Busnel et al 2010;Moghadamzadeh et al 2011;Avramidis et al 2012). Plasma treatment may increase surface wettability and surface free energy of wood (Totolin et al 2008;Wolkenhauer et al 2008;Asandulesa et al 2010;Inbakumar et al 2010;Tang et al 2012) and it contributes in an indirect way to FA reduction.…”

Sisal chemo‐thermomechanical pulp paper with a strongly hydrophobic surface coating produced by a pentafluorophenyldimethylsilane cold plasma

“…The plasma state, recognized as the fourth state of matter, is broadly defined as a gaseous environment composed of charged and neutral species with a net zero electric charge. One of the plasma states is cold plasma or nonequilibrium plasma, also called glow discharge 1. In the cold plasma state the electrons have sufficiently high kinetic energies to induce ionization, excitation and molecular fragmentation processes in low pressure gas environments 2.…”

“…These plasmas are also characterized by very low degrees of ionization; consequently, they are suitable for the modification of organic substrates. The plasma species can also interact with solid‐phase substances generating chemical and morphological changes in the very top layers of the plasma exposed substrates 1. Therefore, cold plasma treatment is a very convenient method for surface modification of solid materials because it is restricted to shallow depth penetration.…”