Evaluation of the process thermal treatment of maple wood saturated water steam in terms of change of pH and color of wood

Dzurenda, Ladislav; Geffert, Anton; Geffertova, Jarmila; Dudiak, Michal

doi:10.15376/biores.15.2.2550-2559

Cited by 14 publications

(8 citation statements)

References 9 publications

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“…Visual inspection of the thermally treated alder wood on the loading surfaces and in the middle of the side surfaces of the sawn blanks, as well as color measurements with the Color Reader CR-10 colorimeter on these surfaces showed that the wood is evenly colored throughout the cross section after 3 h thermal treatment of mode I (t I = 95 ± 2.5 • C). The full-volume coloring of alder wood is realized thanks to the rapid heating of the wood in a pressure autoclave to the required technological temperature with saturated steam over the entire volume of the autoclave, as well as over the entire cross section of the material [16,37]. Rapid heating of the material creates suitable conditions for the processes of extraction of water-soluble substances, hydrolysis of polysaccharides, as well as changes in the structure of lignin of alder wood causing modification of the chromophoric system.…”

Section: Resultsmentioning

confidence: 99%

Changes in the Physical and Chemical Properties of Alder Wood in the Process of Thermal Treatment with Saturated Water Steam

Dudiak

Dzurenda

2021

Coatings

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The paper presents changes in color and selected physico-chemical properties of alder (Alnus glutinosa) wood during the process of thermal treatment of the wood with a saturated steam-air mixture or saturated water steam in the temperature range t = 95–125 °C for τ = 3 to 12 h. During the process of thermal treatment of alder wood, the original light white-gray color changes depending on the temperature and time of modification to soft reddish-brown to dark brown color shades. Color changes of alder wood expressed in the form of the total color difference are in the range of values ∆E* = 2.7–31.7. Measurements of the density of thermally treated alder wood in the dry state indicate that due to the thermal treatment of alder wood, the density decreases by ρ ≤ 4.6% compared to the average density of native alder wood. Due to the hydrolysis of hemicelluloses, in the process of thermal treatment of wet alder wood, its acidity changes in the range of values: pH = 4.9 to 3.1. Analyzes of ATR-FTIR spectroscopy indicate changes in alder wood extractants and hemicellulose degradation. A decrease in unconjugated and an increase in conjugated carbonyls was observed at all temperatures of thermal modification of alder wood. Measurements indicate changes in the lignin of alder wood and the fact that as the temperature increases, the formation of new carbonyls increases, which is reflected in the change of the chromophoric system.

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Section: Resultsmentioning

confidence: 99%

Changes in the Physical and Chemical Properties of Alder Wood in the Process of Thermal Treatment with Saturated Water Steam

Dudiak

Dzurenda

2021

Coatings

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“…However, solid wood used in the production of the best quality products, e.g., musical instruments, is considered to be unique and most precious. On the contrary, authors [4,30] point to the fact that, in addition to solid wood, fibreboards and chipboards are also used in the furniture industry. This was confirmed by the results of the questionnaire survey, where the majority of MSM furniture enterprises (namely 59.7%) work mainly with chipboards and fibreboards.…”

Section: Resultsmentioning

confidence: 99%

“…As refs. [4,30] emphasizes, it is necessary to distinguish the natural gloss of wood, which is influenced by the composition of wood mesh, cut or quality of machining and gloss achieved by the use of chemical coating materials.…”

Section: Resultsmentioning

confidence: 99%

Mapping the Supply of Colour Tones of Wood and Furniture Products in Slovakian Small and Medium-Sized Enterprises

Sedliačiková

Moresová

Kocianová

2021

Forests

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The purpose of the surface treatment of wood products is not only to protect them, but also to make them attractive in relation to the visual aspect through their colour modification. It is therefore important that manufacturers of wood and furniture products pay particular attention to the supply of colour tones of wood. According to colours, wood is divided into groups: red woods (oak, cherry, pine, alder, etc.), brown woods (elm, ash, walnut, etc.), pale woods (hornbeam, spruce, fir, etc.) and green woods (acacia, etc.). The main objective of this paper is to identify the supply of colour tones of wood and furniture products of Slovak micro, small and medium-sized enterprises. An empirical survey was used to map the researched issue in the form of a questionnaire. The results show that Slovak micro, small and medium-sized woodworking and furniture enterprises prefer the quality of wood raw material to its price. At the same time, they mostly manufacture products made of solid wood. Where it is necessary to modify the colour of the wood, enterprises use a process of staining, which enhances the natural colour and grain of the wood. On the other hand, due to the lack of investment capital, they cannot use hydrothermal treatment of wood steaming, which is considered a modern way of modifying the colour tone of the wood. It is essential that Slovak micro, small and medium-sized woodworking and furniture enterprises constantly adapt their production supply in the changing market environment, where they must respond immediately to current trends. In this way, they can sustain and increase their turnover, which will help them overcome the current crisis.

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“…In production, acidity is used to control technological processes. In wood steaming technologies for the purpose of modifying the grain of the wood, the acidity of the wood controls the process of modifying the color of sapwood into darker and reddish-brown shades [31,32].…”

Section: Acidity and Moisture Content Of Beechwoodmentioning

confidence: 99%

Differences in Some Physical and Chemical Properties of Beechwood with False Heartwood, Mature Wood and Sapwood

Dzurenda

Dudiak

Kučerová

2023

Forests

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The article presents the differences in some physical and chemical properties of wood with false heartwood, mature wood, and sapwood of Fagus sylvatica L: density of wood in the dry state, color in the color space CIE L*a*b* on the tangential surface and the planed surface at w = 10 ± 0.5%, as well as moisture and acidity of wet wood. As part of chemical analyses, the relative proportion of cellulose, hemicelluloses, lignin, and extractive substances in individual zones of beechwood in trunks with false heartwood was determined. From the carried out analyses, it follows that the biggest difference between the wood of false heartwood, mature wood, and sapwood is the color of the wood. The red-brown color of the wood with false heartwood in the color space CIE L*a*b* is described by the following coordinate values: L* = 64.9 ± 4.9; a* = 12.9 ± 1.4; b* = 19.6 ± 1.7. The most significant differences between the values of the color space are on the lightness coordinate, where the light ochre-white of mature wood shows a decrease of ∆L* = −14.0 compared with the color of false heartwood, and the white—pale grey color of sapwood shows a decrease of ∆L* = −17.5. The density of dry beechwood with false heartwood is higher by ∆ρ0 = 4.7% than the density of mature wood, and the density of sapwood is ∆ρ0 = 12.3% lower than the density of wood with false heartwood. The exact opposite applies to the acidity of wet beechwood. The results of wet wood acidity measurements also point to certain differences. While the acidity of the wet wood of false heartwood is pH = 5.32 ± 0.13, the acidity of the sapwood is 5.1% lower. The higher acidity of beech heartwood is attributed to the presence of organic acids in polyphenols during heartwood formation. From the comparison of the representation of cellulose, hemicellulose, lignin, and extractive substances, it follows that the relative content of lignin and hemicelluloses is higher in false heartwood than in mature wood and sapwood. On the contrary, the content of holocellulose and cellulose is highest in sapwood. The presented divisions in the physical and chemical properties of beechwood with false heartwood do not limit the use of beechwood in industrial applications, except for a change in color; the definition of color boundaries in the color space CIE L*a*b* creates space for sorting beechwood according to color and can be used to increase the color variety of compositions of construction-carpentry products.

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Evaluation of the process thermal treatment of maple wood saturated water steam in terms of change of pH and color of wood

Cited by 14 publications

References 9 publications

Changes in the Physical and Chemical Properties of Alder Wood in the Process of Thermal Treatment with Saturated Water Steam

Changes in the Physical and Chemical Properties of Alder Wood in the Process of Thermal Treatment with Saturated Water Steam

Mapping the Supply of Colour Tones of Wood and Furniture Products in Slovakian Small and Medium-Sized Enterprises

Differences in Some Physical and Chemical Properties of Beechwood with False Heartwood, Mature Wood and Sapwood

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