Stability of thermosmoothed and precision planed solid wood surfaces

2017 ◽  
Vol 76 (1) ◽  
pp. 243-249
Author(s):  
Zsolt Molnár ◽  
Endre Magoss ◽  
Ingrid Fuchs ◽  
Csilla Csiha
Keyword(s):  
Solid Wood ◽  
Wood Surfaces

scholarly journals Influence of moisture content on the contact angle and surface tension measured on birch wood surfaces

2021 ◽  
Author(s):  
Rami Benkreif ◽  
Fatima Zohra Brahmia ◽  
Csilla Csiha
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Moisture Content ◽  
Solid Wood ◽  
Contact Angles ◽  
Surface Moisture ◽  
Wood Coatings ◽  
The Relationship ◽  
Wood Surfaces

AbstractSurface tension of solid wood surfaces affects the wettability and thus the adhesion of various adhesives and wood coatings. By measuring the contact angle of the wood, the surface tension can be calculated based on the Young-Dupré equation. Several publications have reported on contact angle measured with different test liquids, under different conditions. Results can only be compared if the test conditions are similar. While the roles of the drop volume, image shooting time etc., are widely recognized, the role of the wood surface moisture content (MC) is not evaluated in detail. In this study, the effect of wood moisture content on contact angle values, measured with distilled water and diiodomethane, on sanded birch (Betula pendula) surfaces was investigated, in order to find the relationship between them. With increasing MC from approximately 6% to 30%, increasing contact angle (decreasing surface tension) values were measured according to a logarithmic function. The function makes possible the calculation of contact angles that correspond to different MCs.

scholarly journals Stability of planed and precision planed solid wood surfaces due to wetting

2019 ◽  
pp. 0-0
Author(s):  
Zsolt Molnár ◽  
Ingrid Fuchs ◽  
Sándor Tatai ◽  
Endre Magoss
Keyword(s):  
Solid Wood ◽  
Wood Surfaces

Fe-Sem Characterisation Of Pinus Radiata Solid Wood And Plywood Surfaces Following Machining

IAWA Journal ◽  
2014 ◽  
Vol 35 (1) ◽  
pp. 69-84
Author(s):  
Adya P. Singh ◽  
Bernard S.W. Dawson
Keyword(s):  
Cell Wall ◽  
Pinus Radiata ◽  
Morphological Characteristics ◽  
Solid Wood ◽  
Outer Face ◽  
Subsurface Layers ◽  
Cell Layers ◽  
Wooden Surface ◽  
The Impact ◽  
Wood Surfaces

Selection of coatings for good performance on textured wooden surfaces requires a sound knowledge of the wooden surface textures which result from machining treatments. In this work, Pinus radiata solid wood surfaces were planed, sanded and band-sawn while Pinus radiata plywood surfaces were peeled and rough-sawn. The impact of the various machining treatments was examined by field emission scanning electron microscopy. Particular emphasis was placed on micro-morphological characteristics of surface and sub-surface tissue layers. Planing and sanding resulted in even surface topographies. On planed surfaces, cell deformation and cell wall damage was confined to the outermost cell layers while on sanded surfaces they extended to one or two subsurface layers. Band-sawn solid wood surfaces and rough-sawn plywood surfaces were highly irregular, the result of distortion and loss of tissue masses along the outer face caused by forces generated during sawing. Cell wall level damage, such as delamination and cracking, were present in many cell layers below the surface. Compared to the band-sawn solid wood samples, tissue damage in rough-sawn plywood was more severe. These features are discussed in relation to how micromorphological damage embedded in the surface and subsurface tissue layers can create regions of a highly porous nature with increased surface area which are suited to coating entanglement.

scholarly journals The Impact of a CO2 Laser on the Adhesion and Mold Resistance of a Synthetic Polymer Layer on a Wood Surface

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 242
Author(s):  
Ladislav Reinprecht ◽  
Zuzana Vidholdová
Keyword(s):  
Co2 Laser ◽  
Phase Interface ◽  
European Beech ◽  
Solid Wood ◽  
Synthetic Polymer ◽  
Polymer Layer ◽  
Fagus Sylvatica L ◽  
Mold Resistance ◽  
The Impact ◽  
Wood Surfaces

In the wood industry, laser technologies are commonly applied for the sawing, engraving, or perforation of solid wood and wood composites, but less knowledge exists about their effect on the joining and painting of wood materials with synthetic polymer adhesives and coatings. In this work, a CO2 laser with irradiation doses from 2.1 to 18.8 J·cm−2 was used for the modification of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies /L./ Karst) wood surfaces—either in the native state or after covering them with a layer of polyvinyl acetate (PVAc) or polyurethane (PUR) polymer. The adhesion strength of the phase interface “synthetic polymer—wood”, evaluated by the standard EN ISO 4624, decreased significantly and proportionately in all the laser modification modes, with higher irradiation doses leading to a more apparent degradation and carbonization of the wood adherent or the synthetic polymer layer. The mold resistance of the polymers, evaluated by the standard EN 15457, increased significantly for the less mold-resistant PVAc polymer after its irradiation on the wood adherent. However, the more mold-resistant PUR polymer was able to better resist the microscopic fungi Aspergillus niger Tiegh. and Penicillium purpurogenum Stoll. when irradiation doses of higher intensity acted firstly on the wood adherent.

Influence of the viscosity of UF resins on the radial and tangential penetration into poplar wood and on the shear strength of adhesive joints

Holzforschung ◽  
2012 ◽  
Vol 66 (7) ◽  
pp. 849-856 ◽  
Author(s):  
Ivana Gavrilovic-Grmusa ◽  
Manfred Dunky ◽  
Jovan Miljkovic ◽  
Milanka Djiporovic-Momcilovic
Keyword(s):  
Shear Strength ◽  
Urea Formaldehyde ◽  
Solid Wood ◽  
Depth Of Penetration ◽  
Low Viscosity ◽  
Large Size ◽  
Lap Shear ◽  
The Mean ◽  
Wood Surfaces ◽  
Resin Penetration

Abstract This paper is the final part of a series reporting on the penetration (P) and bonding behaviour of urea-formaldehyde (UF) resins of different viscosities based on different degrees of condensation (DCs). The various resins were applied onto radial and tangential wood surfaces, and solid wood assemblies were prepared by hot pressing. Pt and Pr were observed by evaluation of photomicrographs of the bond lines. The mean and maximum depth of penetration was inversely proportional to the DC. The average depth of Pt was found to be slightly higher than Pr because of the abundance of pits on the radial walls. However, the maximum P was higher in radial direction, due to the elliptic shape of vessels in poplar as well as due to rays improving the resin flow. The lap shear strength (σm) of the same bonded assemblies was determined. Despite the fact that the wood failure always was very high, the σm increased with the better penetration of the resins with low viscosity. The higher strength values measured has been interpreted as a fortification effect of the interphase by bulk resin penetration, as cell wall penetration cannot be expected due to the large size of such resin molecules.

The use of near Infrared Spectroscopy to Identify solid wood Specimens of Swietenia Macrophylla0 (Cites Appendix II)

IAWA Journal ◽  
2011 ◽  
Vol 32 (2) ◽  
pp. 285-296 ◽  
Author(s):  
Jez Willian Batista Braga ◽  
Tereza Cristina Monteiro Pastore ◽  
Vera Teresinha Rauber Coradin ◽  
José Arlete Alves Camargos ◽  
Allan Ribeiro da Silva
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Solid Wood ◽  
Cedrela Odorata ◽  
Carapa Guianensis ◽  
Before And After ◽  
Discriminant Models ◽  
Analysis Models ◽  
Wood Surfaces

Near infrared spectroscopy (NIRS) has been shown effective as a tool for identifying Swietenia when tested as laboratory-processed powder, but testing such powdered wood is not readily adaptable to the fieldidentification of wood. This study explored the efficacy of a fiber optic NIRS scan of solid wood surfaces to separate Swietenia macrophylla King, Carapa guianensis Aubl., Cedrela odorata L., and Micropholis melinoniana Pierre. Transverse, radial, and tangential surfaces were scanned to determine if the surface from which data were collected influenced the spectra recorded. Surfaces were scanned before and after removing the oxidized surface layer of the blocks to test effects of exposure on the spectra. Partial least squares for discriminant analysis models were developed for each taxon separately, based on a calibration set composed of at least 67 samples and a test set with at least 45 samples. The anatomical surface scanned, but not the presence of an oxidized layer, influenced the spectra for each species, necessitating the comparison of the same planes of section. The discriminant models showed small errors for each species, indicating that reliable identifications can be made with NIRS of solid wood surfaces in these species.

Untersuchungen zum Diffusionswiderstand von Holzwerkstoffen | Diffusion resistance of timber materials

2005 ◽  
Vol 156 (3-4) ◽  
pp. 100-103
Author(s):  
Rudolf Popper ◽  
Peter Niemz ◽  
Gerhild Eberle
Keyword(s):  
Relative Humidity ◽  
Water Vapour ◽  
Middle Lamella ◽  
Solid Wood ◽  
Diffusion Resistance ◽  
Water Vapour Diffusion ◽  
Wood Panels ◽  
Vapour Diffusion ◽  
Wet Climate ◽  
Panel Thickness

The water vapour diffusion resistance of timber materials were tested in a wet climate (relative humidity ranging from 100%to 65% at 20 °C) and in a dry climate (relative humidity ranging from 0% to 65% and from 0% to 35% at 20 °c) with variation by relative humidity and vapour pressure gradient. The diffusion resistance of multilayer solid wood panels lies under or within the range of the solid wood (spruce), tending even to a lower range. This can be attributed to the loosely inserted middle lamella of the used solid wood panels, which were not correctly glued by the manufacturer. The diffusion resistance of the solid wood panels increases with decreasing moisture content and decreasing panel thickness, as well as with increasing water vapour gradient from 818 to 1520 Pa. There were clear differences between the tested timber materials. The diffusion resistance of particle composites is strongly dependent on the specific gravity. Due to laminar particles OSBs(Oriented Strand Boards) have a larger diffusion resistance than chipboards. The water vapour diffusion resistance of OSBs lies within the range of plywood.

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