The Effect of Heat Treatment on the Chemical Composition of Ash Wood

Výbohová, Eva; Kučerová, Viera; Andor, Tomáš; Balážová, Žaneta; Veľková, Veronika

doi:10.15376/biores.13.4.8394-8408

Cited by 21 publications

(23 citation statements)

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“…Based on the results (Figure 6), a reduction of 73.36 %, 42.13 % and 23.85.43 % was observed in material treated at 180 ºC for 3, 5 and 7 hours, respectively, while treatments at 200 ºC (3, 5 and 7 h) caused an extracts decrease of 65.21 %, 37.27 % and 13.27 %, respectively, compared to control. The extracts rate progress indicates that in the early stages of treatment, the volatile extracts are volatilized and some nonvolatile extracts are decomposed, resulting in an intense drop, while as the treatment time passes, new extracts (derivatives of hemicelluloses and lignin degradation) appear to be composed, which may also contribute to the darkening of wood color (Sahin et al, 2011;Kamperidou and Barboutis, 2018;Výbohová et al, 2018).…”

Section: Wet Chemical Analysis 32 Mokra Kemijska Analizamentioning

confidence: 99%

Chemical and Structural Characterization of Poplar and Black Pine Wood Exposed to Short Thermal Modification

Kamperidou

2021

Drv. ind. (Online)

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In this study, poplar and black pine wood was exposed to short thermal treatments, aiming to improve some crucial properties. Using wet chemical analyses and Fourier-transform infrared spectroscopy (FT-IR), the influence of these treatments on the chemical composition of the modified species was investigated, as well as on the wood structure, using scanning electron microscopy. With the increase of heat treatment intensity, a mass loss of both species was recorded, attributed to the moisture loss and degradation of volatile compounds, as well as thermally less stable components. In the first treatment stages, the extractives presented a decrease, whereas with the duration and temperature increase, new extractives were formed. Lignin increased its network through ramification, especially at 200 ºC, while holocellulose was found lower in all modified wood categories of both species than in unmodified wood due to the intense decomposition of hemicelluloses. The findings of FT-IR analyses were in line with the chemical analysis results. The thermal modification process made wood materials more hydrophobic and dimensionally stable, providing protection against decomposing factors. At the same time, they were not intensively thermo-degraded, which increased their utilization perspectives and application range as solid wood of enhanced properties, or as wood particles/fibers participating as raw materials in wood-based composite products, wood-polymers composites etc., enhancing their materials compatibility, properties and performance.

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Section: Wet Chemical Analysis 32 Mokra Kemijska Analizamentioning

confidence: 99%

Chemical and Structural Characterization of Poplar and Black Pine Wood Exposed to Short Thermal Modification

Kamperidou

2021

Drv. ind. (Online)

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“…-FTIR analysis (Table 1) showed that the mixture of three used TMWs, comparing to spruce wood particles, had in accordance with the absorbance peaks an evidently higher portion of lignin determined at 1600 cm −1 (1.77:0.75) and unconjugated -C=O groups determined at 1730 cm −1 (2.22:1.09), but on the contrary, a lower portion of guaiacyl lignin determined at 1274 cm −1 (0.30:1.64) and conjugated -C=C-C=O groups determined at 1653 cm −1 (0.06:0.17). Differences in the lignin portion and composition can be attributed: (1) to different wood species (pine/beech/ash TMWs vs. spruce wood) used in the experiment (e.g., generally is known that spruce and other coniferous contain mainly quaiacyl lignin); (2) to creation of new carbonyl and carboxyl groups due to oxidation of wood components in the presence of oxygen at preparation of TMWs; (3) to thermal degradation of hemicelluloses and condensation reactions in TMWs with an indirect increase of lignin and condensed substances similar to natural lignin [71,72].…”

Section: Biologicalmentioning

confidence: 99%

Particleboards from Recycled Thermally Modified Wood

Iždinský

Vidholdová

Reinprecht

2021

Forests

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In recent years, the production and consumption of thermally modified wood (TMW) has been increasing. Offcuts and other waste generated during TMWs processing into products, as well as already disposed products based on TMWs can be an input recycled raw material for production of particleboards (PBs). In a laboratory, 16 mm thick 3-layer PBs bonded with urea-formaldehyde (UF) resin were produced at 5.8 MPa, 240 °C and 8 s pressing factor. In PBs, the particles from fresh spruce wood and mixed particles from offcuts of pine, beech, and ash TMWs were combined in weight ratios of 100:0, 80:20, 50:50 and 0:100. Thickness swelling (TS) and water absorption (WA) of PBs decreased with increased portion of TMW particles, i.e., TS after 24 h maximally about 72.3% and WA after 24 h maximally about 64%. However, mechanical properties of PBs worsened proportionally with a higher content of recycled TMW—apparently, the modulus of rupture (MOR) up to 55.5% and internal bond (IB) up to 46.2%, while negative effect of TMW particles on the modulus of elasticity (MOE) was milder. Decay resistance of PBs to the brown-rot fungus Serpula lacrymans (Schumacher ex Fries) S.F. Gray increased if they contained TMW particles, maximally about 45%, while the mould resistance of PBs containing TMW particles improved only in the first days of test. In summary, the recycled TMW particles can improve the decay and water resistance of PBs exposed to higher humidity environment. However, worsening of their mechanical properties could appear, as well.

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“…열처리에 의해, 목재내의 헤미셀룰로오스가 부분적으로 분해되며, 추출성분을 변화시 키고 새로운 화학 결합을 발생시킨다 (Yun et al, 2015). 아세틸기는 열적으로 불안정하며 아세트산을 형성하도록하고, 이 아세트 산은 헤미셀룰로오스의 열분해에 상당한 영향을 준다 (Výbohová et al, 2018). 헤미셀룰로오스의 양과 구조의 변화는 휨강도와 인장강도를 감소시키며, 셀룰로오스의 분해는 인장 강도의 감소의 주요 원인으로 생각되어진다 (Boonstra et al, 2007).…”

Section: 서 론unclassified

“…Acetyl groups, which are thermally unstable, give rise to acetic acids. These acids have a significant influence on the thermal degradation of hemicellulose (Výbohová et al, 2018). Changes in the amount and structure of hemicellulose reduce bending and tensile strengths, and cellulose degradation is considered to be a major cause of reduced tensile strength (Boonstra et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Effect of Heat Treatment and Particle Size on the Crystalline Properties of Wood Cellulose

Kim¹,

Kim²

2019

Journal of the Korean Wood Science and Technology

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This study was carried out to investigate the effect of heat-treatment and particle size on the crystalline properties of the wood cellulose. The color of wood flours was changed from light yellow in control sample to dark yellow or deep brown by heat treatment at 100℃ to 200℃. Relative crystallinity of the heat treated wood cellulose decreased with decreasing particle size from wood chips to 200 mesh, and there was little change in the crystal width. As the temperature was increased, relative crystallinity of the wood increased and crystal width was not changed. As a result of the FT-IR analysis, it was confirmed that the peaks were gradually decreased at -OH elongation as the heat-treated temperature was increased. The lignin C-H bending of 1425 cm -1 and the hemicellulose C-H bending of 1370 cm -1 did not change with the increase of the heat treatment temperature. In addition, it was revealed that C-C stretching of carbohydrate near 1031 cm -1 decreased with increasing heat treatment temperature. Consequently, it is suggested that particle size and heat treatment affected the crystalline properties of wood cellulose.

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The Effect of Heat Treatment on the Chemical Composition of Ash Wood

Cited by 21 publications

References 0 publications

Chemical and Structural Characterization of Poplar and Black Pine Wood Exposed to Short Thermal Modification

Chemical and Structural Characterization of Poplar and Black Pine Wood Exposed to Short Thermal Modification

Particleboards from Recycled Thermally Modified Wood

Effect of Heat Treatment and Particle Size on the Crystalline Properties of Wood Cellulose

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