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SYNOPSIS. Hydrothermal treatment of wood has a variety of impacts on wood components. This article presents chemical changes in ash and beech wood resulting from influence of autohydrolysis. Depending on the operational conditions used in... more
SYNOPSIS. Hydrothermal treatment of wood has a variety of impacts on wood components. This article presents chemical changes in ash and beech wood resulting from influence of autohydrolysis. Depending on the operational conditions used in the experiment, polysaccharides (mainly hemicellulose portion – primarily xylans, and amorphous portion of cellulose) are depolymerised to monoand oligomers. Sugars in monomeric form are, as a result of hydrolysis processes, dehydrated to low-molecular carbonyl compounds (e.g. 2-furaldehyde, 5-hydroxymethyl-2-furaldehyde). Water-soluble lignin concurrently undergoes degradation reactions. In the hydrolysates there were determined syringaldehyde and vanillin.
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This work evaluates the effect of using selected inorganic chemicals as the main components of waterborne wood preservative systems on the degradation of the cellulose constituent in wood from model samples. The polymeric properties of... more
This work evaluates the effect of using selected inorganic chemicals as the main components of waterborne wood preservative systems on the degradation of the cellulose constituent in wood from model samples. The polymeric properties of cellulose and the homogeneity of the degradation process primarily reflect very well the degree of cellulose deterioration. Whatman papers, as pure cellulose model samples, were impregnated with 10 different 5 wt% solutions of inorganic salts and distilled water and consequently subjected to wet-thermal accelerated aging (T = 85 °C, RH = 65%, for 30 days). The samples were then derivatized to cellulose tricarbanilates (CTCs) through two different procedures (by precipitation in a methanol–water mixture/by evaporation of pyridine from the reaction mixture) and finally analyzed using size exclusion chromatography (SEC). Chemically treated and aged cellulose samples showed different changes in the degree of polymerization (DP) and polydispersity (PD) in ...
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Several polysaccharides augment plant growth and productivity and galvanise defence against pathogens. Such elicitors have ecological superiority over traditional growth regulators, considering their amplified biocompatibility,... more
Several polysaccharides augment plant growth and productivity and galvanise defence against pathogens. Such elicitors have ecological superiority over traditional growth regulators, considering their amplified biocompatibility, biodegradability, bioactivity, non-toxicity, ubiquity, and inexpensiveness. Chitosan is a chitin-derived polysaccharide that has recently been spotlighted among plant scientists. Chitosan supports plant growth and development and protects against microbial entities such as fungi, bacteria, viruses, nematodes, and insects. In this review, we discuss the current knowledge of chitosan’s antimicrobial and insecticidal potential with recent updates. These effects are further explored with the possibilities of chitosan’s active correspondence with phytohormones such as jasmonic acid (JA), salicylic acid (SA), indole acetic acid (IAA), abscisic acid (ABA), and gibberellic acid (GA). The stress-induced redox shift in cellular organelles could be substantiated by the ...
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Key message Fungal infection was outlined as a potential reason for the onset of indented annual growth ring formation during the juvenile phase of hazel wood growth. Annual growth ring indentations resulted from the formation of... more
Key message Fungal infection was outlined as a potential reason for the onset of indented annual growth ring formation during the juvenile phase of hazel wood growth. Annual growth ring indentations resulted from the formation of disturbed zones which originated solely in close proximity to leaf traces. Context Hazel wood is an abnormal type of woody tissue that is formed as a result of exogenous stimuli that may trigger long-term responses in the cambium. Cambial responses produce anatomical alterations in the surrounding xylem tissue that can be observed as an indentation of annual growth rings. The chemical profiles of lignan hydroxymatairesinol may provide an indication of its possible role in the protection of a living tree against the spread of a fungal or microbial infection at the onset of indentation. Aims The objectives of this study were to reveal the anatomical differences in the altered woody tissue of Picea abies hazel wood at both the onset and the later stages of ann...
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This research examined beech bark from a plywood manufacturer to determine its effectiveness in reducing wastes, protecting the ecological environment, and producing more eco-friendly wood-based materials. Beech bark was characterized and... more
This research examined beech bark from a plywood manufacturer to determine its effectiveness in reducing wastes, protecting the ecological environment, and producing more eco-friendly wood-based materials. Beech bark was characterized and evaluated as an adhesive filler in plywood manufacturing, and the effects on the bonding quality and the formaldehyde emission of the plywood panels were examined. Plywood panels were made of formulations with urea-formaldehyde (UF) resin filled with three different concentrations of bark flour (BF): 1 wt%, 3 wt%, and 5 wt%. Compared with solid beech wood, beech bark has a higher lignin and extractives content and lower holocellulose content. It was confirmed that the bark absorbs formaldehyde and the solution with 5 wt% of bark absorbed the most formaldehyde. Panels with UF/BF formulations at a bark content of 1 wt%, 3 wt%, and 5 wt% had higher wet bonding strengths than those made with the control sample. The most significant reduction in formaldehyde emission (up to 42.3%) of plywood panels and the achievement of high bonding strength was observed for UF/BF samples with a bark concentration of 5 wt%. The bonding strength of plywood panels with all investigated BF concentrations met the requirements of the EN 314-2 standard.
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The aim of this work is to propose the first model hypothesis and function for predicting the efficacy of deacidification. We have used the dDEA as the first basic factor influencing the efficacy. The resulting relationship is based on... more
The aim of this work is to propose the first model hypothesis and function for predicting the efficacy of deacidification. We have used the dDEA as the first basic factor influencing the efficacy. The resulting relationship is based on the best achieved reliable η data and related dDEA data, from mass deacidification technologies used for the lifetime and usability increase of millions of books, historical documents worldwide. The resulting η predicting function is as follows η = 0.732984+0.125612*dDEA^(-0.214237). This first 1D function can serve as an impulse for continuing improvement of the prediction, and 2D, 3D and multidimensional models. It can be used for comparisons and connecting η with η-characteristic mechanical, physical, cellulose solution properties; the prediction can serve for continuing improvement of efficacy of the conservation technology in increasing the paper carriers of information, documents longevity and usability.
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Physico-chemical changes to ThermoWood produced from Norway spruce (Picea abies L.) with the dimensions 20 mm × 20 mm × 10 mm were evaluated as a function of thermal loading at a flame ignition temperature (FIT) and spontaneous ignition... more
Physico-chemical changes to ThermoWood produced from Norway spruce (Picea abies L.) with the dimensions 20 mm × 20 mm × 10 mm were evaluated as a function of thermal loading at a flame ignition temperature (FIT) and spontaneous ignition temperature (SIT). The extractives, cellulose, holocellulose, and lignin contents were determined by wet chemistry methods. Carbohydrates and cellulose changes were investigated by high-performance liquid chromatography and size exclusion chromatography. The dimensional characteristics of the fibers (length, width, and shape factor) were measured. After thermal loading, an increase in both the cellulose (FIT – 33.1%, SIT – 64.6%) and lignin (FIT – 28.3%, SIT – 63.4%) contents and a decrease in the extractives content (approximately 8% to 9%) were observed. The increase in the cellulose content was attributed to structural changes (carbonization and crosslinking). The lignin content increased because of condensation and its greater thermal stability c...
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In order to not limit the possibilities of using wood due to its flammability, the implementation of fire protection is an essential requirement. An integral part of the research on the fire protection of wood is the determination of the... more
In order to not limit the possibilities of using wood due to its flammability, the implementation of fire protection is an essential requirement. An integral part of the research on the fire protection of wood is the determination of the effectiveness of the applied protective means and their effect on changing its behavior under fire conditions. In this work, samples of spruce wood (Picea abies (L.) H. Karst) (50 mm × 40 mm × 10 mm) were treated with an aqueous solution of sodium silicate and different types of expandable graphite flakes that were applied to the surface of the samples. The fire characteristics of the samples were studied using a non-standard test method, the radiant heat source test, which was used to determine the mass loss, burning rate, and ignition time of the test samples, and the measurement was carried out via visual recording with a thermal camera. The results of the laboratory test method showed a significant positive effect of the application of all types...
Research Interests: Coatings()
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One of the strategies to improve the fire resistance of wood is to use flame retardants. It would be best to find an ecological, nonhalogenated flame retardant to improve the fire protection properties. In this work, oak wood (Quercus... more
One of the strategies to improve the fire resistance of wood is to use flame retardants. It would be best to find an ecological, nonhalogenated flame retardant to improve the fire protection properties. In this work, oak wood (Quercus robur L.) samples were treated with an aqueous solution of sodium silicate and expandable graphite flakes, which were applied to different parts of the samples: only on the top, on the sides and together on the top and sides of samples. The fire characteristics of samples were studied by a non-standard test method—a radiant heat source test which is used to determine the mass loss and ignition time of the tested samples (50 mm × 40 mm × 10 mm), and the measurement was carried out using a visual recording of a thermal camera. The results of the laboratory test method showed a significant positive effect of the application of the retardant treated only on the top and together on the top and the sides of the samples in terms of decreasing the mass loss an...
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The present study discusses uncatalyzed and acid catalyzed organosolv pulping of popular wood carried out at a temperature of 140°. A mixture of methanol-water was used as a liquor (52:48% v/v). For catalysed delignifications, 0.01 M H 2... more
The present study discusses uncatalyzed and acid catalyzed organosolv pulping of popular wood carried out at a temperature of 140°. A mixture of methanol-water was used as a liquor (52:48% v/v). For catalysed delignifications, 0.01 M H 2 SO 4 , 0.02 M HNO 3 and 0.015 M (COOH) 2 solutions in the same solvent were used. The effect of the corresponding esters did not differ much from that of the acids.A partial delignification of chips with white-rot fungus Coriolum versicolor prior to uncatalyzed pulping improved the pulp properties. A 23% loss of cellulose due to chips biodegradation excluded this pretreatment from further experiments. Similarly, the application of peracetic acid solutions did not improve the pulp properties adequately. A comparison of the pulps properties obtained from catalysed pulpings pointed out the highest delignification efficiency of 0.02 M solution of HNO 3 , given by the highest hydroxonium ions concentration in a liquor. The application of 0.01 M sulphuric...
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Wood and wood products in proper conditions are durable for centuries. However, there are bio-based materials and thus are prone to deterioration by fungi, insects, and other organism. Another undesirable feature of wood products is their... more
Wood and wood products in proper conditions are durable for centuries. However, there are bio-based materials and thus are prone to deterioration by fungi, insects, and other organism. Another undesirable feature of wood products is their flammability. Wood and wood products are protected by treatment with various chemicals for prolong their longevity, however many of them have adverse impact at their properties as well at the environment; e.g. waterborne preservative treatments generally reduce the mechanical properties of wood. This paper compiles important research findings related to both negative and positive impacts of inorganic chemicals on wood for better understanding and comprehension of the chemical aspect of this problem.
Materials analysed-model compounds: 0-acetyl salicylic acid (analytical grade), a-naphtyl acetate (technical grade), dulcit hexaacetate This compound was prepared by repeated acetylation of dulcit with an acetic acid anhydride-pyridine... more
Materials analysed-model compounds: 0-acetyl salicylic acid (analytical grade), a-naphtyl acetate (technical grade), dulcit hexaacetate This compound was prepared by repeated acetylation of dulcit with an acetic acid anhydride-pyridine mixture (l : l , v:v). The crude product was purified by extraction with CH2C1,, dried over anhydrous Na2S04. The compound was isolated by evaporation of CH,C1, in vacuum.
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The ability of lignin-degrading microorganisms Phanerochaete chrysosporium to attack polyethylene was investigated on the series of the polymer blends containing 10, 20 and 30% lignin. Measurement of tensile strenght after 30-days... more
The ability of lignin-degrading microorganisms Phanerochaete chrysosporium to attack polyethylene was investigated on the series of the polymer blends containing 10, 20 and 30% lignin. Measurement of tensile strenght after 30-days cultivation showed that the mechanical properties of the polymer blends were decreased with the increase of lignin content. The isolation of oligomer fraction from biodegraded polymer blends and their characterization by GPC, UV and IR spectroscopy indicates that biotransformation of lignin component during cultivation process is accompanied with degradation of polethylene matrix.
A series of sound and by selected white-rot fungi (P. chrysosporium and C. subvermispora biodegraded beech wood chips were submitted to mild acidic and alkaline hydrolysis. Disintegrated samples were oxidized by means of nitrobenzene... more
A series of sound and by selected white-rot fungi (P. chrysosporium and C. subvermispora biodegraded beech wood chips were submitted to mild acidic and alkaline hydrolysis. Disintegrated samples were oxidized by means of nitrobenzene oxidation and products were analysed by high pressure chromatography. The obtained analytical data point out at increased extent of „in situ“ lignin condensation and increase in molar syringyl to guajacyl ratio in the oxidation products of acid- and alkali-treated sound and biodegraded materials. Reduced extent of condensation of lignin in the both biodegraded samples in acid- and alkaline environments hints at approx. up to 15 % diminished reactivity of enzymatically modified lignin. This may partly explain reduction of residual lignin content in the pulps from bio-pretreated beech wood cooked to equal yields as the pulps from sound material. Key words: beech wood, biotic degradation, nitrobenzene oxidation, condensation of lignin, reactivity
Spruce wood (Picea abies L.) boards with dimensions of 23x80x700 min were thermally loaded by nfrared heating at initial moisture values of 9% and 25%, respectively. The heat caused the colour alteration of wood, alongwith the increase of... more
Spruce wood (Picea abies L.) boards with dimensions of 23x80x700 min were thermally loaded by nfrared heating at initial moisture values of 9% and 25%, respectively. The heat caused the colour alteration of wood, alongwith the increase of the lignin and extractives amount and decrease of the amount of methoxyl groups in lignin. Alterations of dioxan lignin were determined by gel permeation chromatography (GPC) and infrared spectroscopy (FT-IR). Simultaneous depolymerisation and condensation reactions take place, due to temperature influence. At lower temperatures, lignin is predominantly degraded (mainly the alkylarylether bonds cleave) while, at higher temperatures, the condensation reactions are dominant, being accompanied by diphenylmethane structures formation. The moisture content of 9% has a higher influence on alterations than a moisture value of 25%.
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The yeast-degradation of lipophilic extractices in sound and biologically decayed beech was examined. All tested yeast strains Sporobolomyces salmonicolor, Geotrichum capitatum and Geotrichum klebahnii removed higher amount extractives... more
The yeast-degradation of lipophilic extractices in sound and biologically decayed beech was examined. All tested yeast strains Sporobolomyces salmonicolor, Geotrichum capitatum and Geotrichum klebahnii removed higher amount extractives from sound wood than from decayed wood. The degradation of extractives was examined HPLC and FTIR spectroscopy of acetone extracts obtained by the extraction of beech wood samples before and after yeast treatment. It was revealed that the used yeast microorganisms remove from 40 to 60% of extractives. Sp. salmonicolor was the most efficient yeast strain in degrading extractive constituents. The obtained results are contribution to development of new biological approaches for controlling pitch problems in pulp and paper mills.
Research Interests: Wood()
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In this paper there were described the changes of maple wood (Acer pseudoplatanus L.) saccharides after the irradiation by CO2 laser (wavelength 10.6 µm) in the equipment LCS 400. The irradiation speed was 1.0-3.2 cm.s-1, irradiation dose... more
In this paper there were described the changes of maple wood (Acer pseudoplatanus L.) saccharides after the irradiation by CO2 laser (wavelength 10.6 µm) in the equipment LCS 400. The irradiation speed was 1.0-3.2 cm.s-1, irradiation dose 17.9-57.3 J.cm-2. Saccharides were determined by gas chromatography as aldonitrilacetates, cellulose in accordance with Kürschner and Hoffer. At the irradiation of maple wood surface by CO2 laser the amount of saccharides decreases in dependence of energy amount. The mild decrease of saccharides takes place at the irradiation dose higher than 26.1 J.cm-2, the marked decrease begins at the irradiation dose higher than 35.8 J.cm-2. Hemicelluloses degrade more quickly, the changes take place also in cellulose. The total decrease of saccharides at the highest irradiation dose was 58.79 % from the initial amount of saccharides in the sample without irradiation.
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SYNOPSIS. The information of saccharides qualitative presence and quantitative abundance in lignocellulosics is very important from the viewpoint of the saccharides structure knowledge. In the paper the optimization is described of sugar... more
SYNOPSIS. The information of saccharides qualitative presence and quantitative abundance in lignocellulosics is very important from the viewpoint of the saccharides structure knowledge. In the paper the optimization is described of sugar aldonitrilacetates capillary gas chromatography method and its evaluation for the separation and quantification of carbohydrates in various samples. For the monosaccharides identification six aldonitrilacetates of standard carbohydrates (rhamnose, arabinose, xylose, manose, glucose, galactose) were prepared. Three sulphate spruce pulps were hydrolysed by Saeman et al. (1954) method. Also holocellulose was prepared by Wise et al. (1946) method from beech wood before and after prehydrolysis. Then the samples were derivatised to aldonitrilacetates. The gas chromatography was performed on Fisons 8310 DPFC GC with flame ionisation detector and DB-5 capillary column with inositol as an internal standard. The retention times, response factors, resolution a...
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The aim of this work is to propose the first model hypothesis and function for predicting the efficacy of deacidification. We have used the dDEA as the first basic factor influencing the efficacy. The resulting relationship is based on... more
The aim of this work is to propose the first model hypothesis and function for predicting the efficacy of deacidification. We have used the dDEA as the first basic factor influencing the efficacy. The resulting relationship is based on the best achieved reliable η data and related dDEA data, from mass deacidification technologies used for the lifetime and usability increase of millions of books, historical documents worldwide. The resulting η predicting function is as follows η = 0.732984+0.125612*dDEA^(-0.214237). This first 1D function can serve as an impulse for continuing improvement of the prediction, and 2D, 3D and multidimensional models. It can be used for comparisons and connecting η with η-characteristic mechanical, physical, cellulose solution properties; the prediction can serve for continuing improvement of efficacy of the conservation technology in increasing the paper carriers of information, documents longevity and usability.
Research Interests: Wood()
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In protecting cultural heritage, deacidification is used to stabilize acidic papers, ensuring the neutralization of acids present in the paper. But in the process of aging, several mechanisms of degradation occur simultaneously.... more
In protecting cultural heritage, deacidification is used to stabilize acidic papers, ensuring the neutralization of acids present in the paper. But in the process of aging, several mechanisms of degradation occur simultaneously. Therefore, substances used to stabilize the paper should contain an antioxidant component in addition to the deacidifying component. The effect of the antioxidant (hindered amine light stabilizers—HALS type) on the stabilization of lignin-containing acid papers during accelerated aging was studied in this work. The effective deacidification component was magnesium; the solvent was hexamethyldisiloxane (HMDSO). The 4-amino-2,2,6,6-tetramethylpiperidine series of hindered amine light stabilizers (HALS) was selected as appropriate for creating a modifying system based on HMDSO. The modification system was tested on samples of a model test acid lignin-containing paper (NOVO) and naturally aged acidic paper from the real book. The addition of substances to the pr...
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This article deals with the possibility of valorizing wood waste from grapevine cultivation of the varieties Pesecká leánka (white graft) and Frankovka modrá (red graft), grown in Slovakia. From the point of view of chemical composition,... more
This article deals with the possibility of valorizing wood waste from grapevine cultivation of the varieties Pesecká leánka (white graft) and Frankovka modrá (red graft), grown in Slovakia. From the point of view of chemical composition, two methods (water and ethyl alcohol) were performed for the determination of extractives, acid-insoluble (Klason) lignin, and structural carbohydrates, and FTIR spectra of the grape samples were recorded. Mechanical strength, compression test parallel to the grain, and morphological properties (fiber length, width, and shape factor using a fiber tester) were carried out. The energy potential of grapevines was evaluated by determining the calorific value. According to the results, the relatively high content of carbohydrates (54.19%–55.27%) provides a prerequisite for acid or enzymatic hydrolysis to produce monosaccharides or second-generation bioethanol. FTIR spectra confirmed the higher content of lignin and cellulose in red grapes. The compressio...
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Black locust is a fast-growing deciduous tree species with multiple industrial purposes due to its valuable traits. However, the heterogeneity of colour distribution between sapwood and heartwood limits its application. Thermal... more
Black locust is a fast-growing deciduous tree species with multiple industrial purposes due to its valuable traits. However, the heterogeneity of colour distribution between sapwood and heartwood limits its application. Thermal modification is an environment-friendly technology for improving various wood properties, especially dimensional stability, decay resistance, and colour homogeneity. In this work, black locust (Robinia pseudoacacia L.) wood samples were thermally modified at temperatures of 160, 180, and 210 °C. Extractives and main wood components were analysed by wet chemical methods, colour was measured by spectrometry, and structural changes by Fourier transform infrared spectroscopy. The obtained results show that the darkening of black locust wood, unlike other wood species of the temperate zone, is mainly caused by changes in extractives. Their content decreases during thermal treatment, but new chromophores are formed, especially in quinones. Degradation of hemicellul...
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Distribution of resin ducts per unit area of wood within annual growth rings