Colour stability of surface finishes on thermally modified beech wood

2021 ◽  
Vol 114 ◽  
pp. 116-124
Author(s):  
Gabriela Slabejová ◽  
MÁRIA ŠMIDRIAKOVÁ
Keyword(s):  
Surface Finish ◽  
Beech Wood ◽  
Surface Finishing ◽  
Colour Stability ◽  
Colour Difference ◽  
Surface Finishes ◽  
Before And After ◽  
Thermally Modified Wood ◽  
Wood Surfaces ◽  
Modified Wood

Colour stability of surface finishes on thermally modified beech wood. The paper deals with the influence of the type of transparent surface finish on the change of colour of the surfaces of native beech wood and thermally modified wood. At the same time, the colour stability of three surface finishes on the surfaces of native and thermally modified beech wood was monitored. Beech wood was thermally modified at temperature of 125 °C for 6 hours. The thermal treatment was performed in a pressure autoclave APDZ 240, by the company Sundermann s.r.o in Banská Štiavnica. Three various types of surface finishes (synthetic, wax-oil, water-based) were applied onto the wood surfaces. The colour of the surfaces of native wood and thermally modified wood was measured in the system CIELab before and after surface finishing; the coordinates L*, a*, b*, C*ab and h*ab were measured. From the coordinates measured before and after surface finishing, the differences were calculated and then the colour difference ∆E* was calculated. Subsequently, the test specimens with the surface finishes were exposed to natural sunlight, behind glass in the interior for 60 days. The surface colour was measured at specified time of the exposure (10, 20, 30, 60 days). The results showed that the colour of the wood surfaces changed after application of the individual surface finishes; and the colour difference reached a change visible with a medium quality filter up to a high colour difference. The wax-oil surface finish caused a high colour difference on native wood and on thermally modified wood as well. On native beech wood, the lowest colour difference after exposure to sunlight was noticeable on the synthetic surface finish. On the surface of wood thermally modified, after exposure to sunlight, the lowest colour difference was noticeable on the surface with no surface finish.

scholarly journals Colour Stability of Thermally Modified Wood during Short-Term Photodegradation

BioResources ◽  
2014 ◽  
Vol 9 (4) ◽  
Author(s):  
Laszlo Tolvaj ◽  
Robert Nemeth ◽  
Zoltan Pasztory ◽  
Laszlo Bejo ◽  
Peter Takats
Keyword(s):  
Colour Stability ◽  
Short Term ◽  
Thermally Modified Wood ◽  
Modified Wood

The effect of air plasma treatment at atmospheric pressure on thermally modified wood surfaces

2016 ◽  
Vol 50 (6) ◽  
pp. 1227-1241 ◽  
Author(s):  
Daniela Altgen ◽  
Georg Avramidis ◽  
Wolfgang Viöl ◽  
Carsten Mai
Keyword(s):  
Plasma Treatment ◽  
Atmospheric Pressure ◽  
Air Plasma ◽  
Thermally Modified Wood ◽  
Wood Surfaces ◽  
Air Plasma Treatment ◽  
Modified Wood

Effect of Electrolyte on the Surface Smoothness Obtained by Electropolishing of Stainless Steel

2012 ◽  
Vol 713 ◽  
pp. 55-60 ◽  
Author(s):  
M. Hernando ◽  
Pedro Jose Núñez López ◽  
Eustaquio García Plaza ◽  
R. Trujillo
Keyword(s):  
Stainless Steel ◽  
Surface Finish ◽  
Chromic Acid ◽  
Bath Temperature ◽  
Surface Finishing ◽  
Initial Surface ◽  
Surface Finishes ◽  
Finishing Process ◽  
Steel Aisi ◽  
Stainless Steel Aisi

Electropolishing is a surface finishing process of metals and alloys that enhances brilliant surface finishes with low surface roughness values. The most widely used electrolytes for the electropolishing of stainless steel are varying concentrations of phosphoric and sulphuric acid, and occasionally additives such as chromic acid. The objective of this study was to assess the performance of three commonly used industrial electrolytes in terms of the surface finish of electropolished stainless steel AISI 316L. Each electrolyte had varying sulphuric-phosphoric acid combinations with or without chromic acid. The following electropolishing conditions were assessed: current density, bath temperature, electropolishing time, and initial surface texture. The results revealed that adding chromic acid to the electrolyte did not significantly enhance surface finish, and electropolishing ranges were quite similar for all three electrolytes.

scholarly journals Surface topography and bacterial adhesion of CAD/CAM resin based materials after application of different surface finishing techniques

2018 ◽  
Vol 17 ◽  
pp. 1-11
Author(s):  
Raphael Meneghetti Hamerschmitt ◽  
Paulo Henrique Tomazinho ◽  
Kaíke Lessa Camporês ◽  
Carla Castiglia Gonzaga ◽  
Leonardo Fernandes da Cunha ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Topography ◽  
Surface Finish ◽  
Bacterial Adhesion ◽  
Resin Composite ◽  
The Other ◽  
Surface Finishing ◽  
Roughness Parameters ◽  
Surface Finishes ◽  
Hybrid Ceramic

Aim: This study evaluated the surface topography and bacterial adhesion of a hybrid ceramic and a nano ceramic resin composite after different surface finishes. Methods: Hybrid ceramic (Vita Enamic, VITA - EN) and nano ceramic resin composite (Lava Ultimate, 3M/ESPE - LV) blocks of 12 x 14 x 18 mm were cut into 1 mm slices. Each slice was divided into four specimens (6 x 7 mm) that were randomly allocated into 4 groups (n=8) according to the surface finishing: CTL - without surface finish (control); DB - wear with a diamond bur; VT - polishing system for hybrid ceramic (VITA); and DD - polishing system for ceramics (Dedeco). The specimens were analyzed regarding surface roughness parameters (Ra, Rz, Rq), sterilized and subjected to bacterial adhesion. Representative specimens from each group were observed by SEM and Confocal Laser Scanning Microscopy. Data were submitted to two-way ANOVA and Tukey's test (α=0.05). Results: EN had lower surface roughness and bacterial adhesion than LV (p<0.05), regardless of the surface finish. The highest values for all roughness parameters was observed in LVDB group, differing from the other groups, which were not significantly different. Smaller bacterial adhesion values (CFU/mL) were observed for ENDD and ENVT, which differed significantly from the other groups, except ENCTL. For LV groups there was no significant difference between the different surface finishes (p>0.05). The type of material and surface finish system significantly interfered with surface roughness parameters and bacterial adhesion. The hybrid ceramic performed better after polishing than the nano-ceramic resin. Conclusion: An adequate finishing/polishing technique should always be performed after any kind of adjustment to indirect restorations made with these materials tested.

The effect of mechanical treatment of beech wood surface on quality of surface finish

2019 ◽  
Vol 106 ◽  
pp. 99-106
Author(s):  
GABRIELA SLABEJOVÁ ◽  
MÁRIA ŠMIDRIAKOVÁ
Keyword(s):  
Film Thickness ◽  
Surface Finish ◽  
Wood Surface ◽  
Mechanical Treatment ◽  
Beech Wood ◽  
Impact Resistance ◽  
Coating Materials ◽  
Surface Finishes ◽  
The Impact

The effect of mechanical treatment of beech wood surface on quality of surface finish. The paper deals with the quality of three surface finishes intended into interior. Three types of coating materials were tested (polyurethane, waterborne, wax). Each type of the surface finish was created on beech wood surface in three various coating thicknesses. The coating thicknesses differed in number of coatings of the coating material. The surface finishes were evaluated according to the impact resistance and the resistance to abrasion. The polyurethane surface finish showed the lowest resistance to abrasion. If the film thickness was increasing, the resistance to abrasion was decreasing. The greatest differences in the resistance to abrasion, depending on the wood surface treatment, were found on the wax surface finish. In general, the waterborne surface finish showed the best resistance to abrasion. Pressing the wood surface before finishing increased the impact resistance of all three surface finishes. The damage of the surfaces was only of grade 2 (No cracks on the surface and the intrusion was only slightly visible). The lowest impact resistance of the surface finishes was found on grinded wood surface; the damage was graded as 4 (Visible large cracks at the intrusion). At the drop height of 400 mm, the effect of the film thickness on the impact resistance was no longer present on all differently mechanically treated surfaces.

scholarly journals Hyperspectral Imaging Surface Analysis for Dried and Thermally Modified Wood: An Exploratory Study

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Olena Myronycheva ◽  
Ekaterina Sidorova ◽  
Olle Hagman ◽  
Margot Sehlstedt-Persson ◽  
Olov Karlsson ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Multivariate Calibration ◽  
Treated Wood ◽  
Wavelength Assignment ◽  
Chemical Information ◽  
Wavelength Band ◽  
Thermally Modified Wood ◽  
Wood Surfaces ◽  
Modified Wood

Naturally seasoned, kiln-dried, and thermally modified wood has been studied by hyperspectral near-infrared imaging between 980 and 2500 nm in order to obtain spatial chemical information. Evince software was used to explore, preprocess, and analyse spectral data from image pixels and link these data to chemical information via spectral wavelength assignment. A PCA model showed that regions with high absorbance were related to extractives with phenolic groups and aliphatic hydrocarbons. The sharp wavelength band at 2135 nm was found by multivariate analysis to be useful for multivariate calibration. This peak represents the largest variation that characterizes the knot area and can be related to areas in wood rich in hydrocarbons and phenol, and it can perhaps be used for future calibration of other wood surfaces. The discriminant analysis of thermally treated wood showed the strongest differentiation between the planed and rip-cut wood surfaces and a fairly clear discrimination between the two thermal processes. The wavelength band at 2100 nm showed the greatest difference and may correspond to stretching of C=O-O of polymeric acetyl groups, but this requires confirmation by chemical analysis.

scholarly journals Sorption and diffusion properties of untreated and thermally modified beech wood dust

2021 ◽  
Author(s):  
Jerzy Majka ◽  
Tomasz Rogoziński ◽  
Wiesław Olek
Keyword(s):  
Moisture Content ◽  
Beech Wood ◽  
Thermal Modification ◽  
Dust Particles ◽  
Wood Dust ◽  
Water Diffusivity ◽  
Thermally Modified Wood ◽  
And Diffusion ◽  
Diffusion Properties ◽  
Modified Wood

AbstractDynamic water vapor sorption experiments were carried out using beech wood dust (from untreated and thermally modified wood) of two-particle sizes, (< 25 and 80–250 µm), obtained from abrasive sanding. Sorption isotherms were parameterized with the GAB and GDW models. Dust from thermally modified wood had significantly lower equilibrium moisture content compared to dust from untreated material, due to the reduction in primary sorption sites in treated material. The observed changes were quantified by the coefficients of the GAB and GDW models. Thermal modification and size of wood dust particles had no influence on binding energy of water molecules being linked to the secondary sorption sites. Water diffusivity decreased significantly with increasing moisture content, but only for monolayer sorption. For higher moisture content values, water diffusivity was practically independent of moisture content. These results were found for untreated and thermally modified material as well as for both dust size fractions. The influence of thermal modification on water diffusivity was unclear, which is attributed to the diffusion model, which represents dust particles as spheres and assumes instant hygroscopic equilibrium. Overall, this study indicates that the effectiveness of filtration processes likely depends strongly on sorption and diffusion properties of wood dust only at low moisture contents within the hygroscopic range.

Analysis of Surface Finishing and Pressing Time in Wooden Pieces for the Use of Wood Waste in the Furniture Industry

2019 ◽  
Vol 69 (3) ◽  
pp. 239-244
Author(s):  
Carlos Mario Gutiérrez ◽  
Beatriz Elena Ángel ◽  
Julia Silva ◽  
Asher Kiperstok ◽  
Rita Cunha ◽  
...  
Keyword(s):  
Surface Finish ◽  
Polyvinyl Acetate ◽  
Glue Line ◽  
Surface Finishing ◽  
Furniture Industry ◽  
Pressing Time ◽  
Surface Finishes ◽  
Eucalyptus Wood ◽  
Optimal Surface

Abstract This article analyzes the behavior of surface finish and pressing time in glued pieces of eucalyptus wood. The importance of the study lies in verifying the influence of two variables (surface finish and pressing time) on the gluing of wood pieces for the furniture industry over time. For this purpose, the quality of adhesion of Eucalyptus urograndis wood pieces with polyvinyl acetate adhesive and the behavior of the wood to shear in the glue line are evaluated. It was necessary to produce test specimens according to the ABNT-NBR 7190 standard; three different surface finishes were evaluated on the faces to be adhered and three different cold pressing times, a variable that has not been analyzed in previous studies. It was possible to determine the shear resistance in the glue line and also to observe the percentage of wood failure when performing the destructive test on the test specimen 1 year after being glued. The highest shear strength was obtained for test specimens without surface finish and with a pressing time of 24 hours. With the results obtained in this study, the optimal surface finish and pressing time to be used in the furniture industry is evidenced.

scholarly journals OPTIMIZATION OF PROTECTIVE COATING COMPONENTS OF THERMOMODIFIED WOOD TO THE EXPOSURE OF WATER

2021 ◽  
pp. 101-109
Author(s):  
Yu. Tsapko ◽  
◽  
A.Yu. Gorbachova ◽  
S.N. Mazurchuk ◽  
O. Bondarenko ◽  
...  
Keyword(s):  
Water Absorption ◽  
Protective Coating ◽  
Moisture Absorption ◽  
Thermal Modification ◽  
Wood Products ◽  
Operating Conditions ◽  
Photochemical Degradation ◽  
Thermally Modified Wood ◽  
Wood Surfaces ◽  
Modified Wood

Abstract. Paints and varnishes are used to a large extent to protect wood surfaces in outdoor conditions, as they are easy to maintain and reapply. Also, when developing a coating, manufacturers are guided by the need to obtain a number of properties that generally determine its ability to protect against moisture. To obtain a protective coating that meets the specified requirements, it is necessary that the components that make up the coating belong directly to the group of protective materials or form such compounds under operating conditions, be able to adhere to the surface of the product. It was found that thermal modification provides a decrease in water absorption of wood. Additional processing of the wood surface helps to reduce moisture absorption by 2 times, and for samples modified at a temperature of 220 °C – 3 times. Geometric dimensional stability is also improved by a factor of 2. The effect of heat treatment on the water absorption of wood is somewhat less – for samples modified at 190 and 220 °C for more than 10 hours. Protective substances for thermally modified wood provided similar protection of open thermally modified surfaces of wood from the effects of water. The positive effect of thermal modification on a decrease in the level of water absorption has been established. It has been proven that it is temperature that has a significant effect on such changes. Since the protective coating is also susceptible to photochemical degradation, it is very important to renew it in a timely manner in accordance with the manufacturer's instructions for the pleasant appearance of wood surfaces during external use. The optimal ratio of components in the surface layer of thermally modified wood has been determined, which ensures the fulfillment of the task, namely for a mixture of oil and wax: the density of a wood – 724 kg/m3; oils – 70.0%; wax – 17.5%. Therefore, such treatment is beneficial for the protection and aesthetic appeal of wood products.

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