Color changes of ash wood (Fraxinus excelsior L.) caused by thermal modification in air and steam

Gawron, Jakub; Marchwicka, Monika

doi:10.5604/01.3001.0015.6639

Cited by 3 publications

(4 citation statements)

References 10 publications

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“…According to Figure 2 and Table 1, as the vacuum heat treatment temperature increased, the heat treatment induced a significant decrease in L* values from 74.56 to 49.34, an increase in redness (a* values) from 2.64 to 6.97, while b* values showed a tendency of first increasing and then decreasing, which indicates that after the vacuum heat treatment the bamboo fibers became darker and experienced the transition from green to red. Moreover, the total color change (parameter ∆E) ranged from 2.14 to 25.65, implying that the color change of the heat treatment bamboo fibers above 160 • C could be clearly seen by the human eye as an obviously different color (∆E > 5) [24]. The increase of chromophore groups and the decrease of auxochromic groups in the bamboo fibers are the fundamental reasons for the deepening of their color [25].…”

Section: Effect Of Vacuum Heat Treatment On Surface Color Of Bamboo F...mentioning

confidence: 99%

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Surface Characteristics of Thermally Modified Bamboo Fibers and Its Utilization Potential for Bamboo Plastic Composites

et al. 2022

Materials

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Bamboo fibers are considered as a more attractive option for the reinforcement of wood plastic composites as compared to wood fiber due to its fast growth rate and good toughness. Heat treatment is an environment-friendly method of improving the integrated performance of bamboo materials. This paper highlights the heat treatment of bamboo fiber for suitable properties as reinforcements in bamboo plastic composites. The effects of vacuum heat treatment on the surface characteristics of bamboo fibers and the properties of bamboo plastic composites were analyzed by studying the chemical composition, surface elements and polarity of bamboo fiber before and after treatment, and the physical and mechanical properties of bamboo plastic composite. The results showed that after vacuum heat treatment, the bamboo fibers became darker and experienced a transition from green to red. Moreover, FTIR, XPS and contact angle analysis indicated that the hemicellulose content, the oxygen/carbon ratio and the polar component of the bamboo fiber had a decreasing trend as the treatment temperature increased. In addition, the 24 h water absorption and the 24 h thickness expansion rate of the water absorption showed a trend of first decreasing and then increasing as the treatment temperature increased, while the bending performance of bamboo plastic composite showed a trend of increasing first and then decreasing as a result of increased treatment temperature. Therefore, a combined process of vacuum heat treatment and the addition of MAPE could improve the physical and mechanical properties of bamboo plastic composites to a certain extent.

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Section: Effect Of Vacuum Heat Treatment On Surface Color Of Bamboo F...mentioning

confidence: 99%

“…seen by the human eye as an obviously different color (ΔE > 5) [24]. T mophore groups and the decrease of auxochromic groups in the ba fundamental reasons for the deepening of their color [25].…”

Section: Effect Of Vacuum Heat Treatment On Surface Color Of Bamboo F...mentioning

confidence: 99%

Surface Characteristics of Thermally Modified Bamboo Fibers and Its Utilization Potential for Bamboo Plastic Composites

et al. 2022

Materials

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“…These findings indicate that enzymatic treatments can induce observable changes in the color attributes of bamboo fibers. The alterations in the color of enzymatically treated bamboo fibers are discernible to the naked eye, as they exceed the average capability of humans to distinguish color differences (∆E* greater than 5) [22].…”

Section: Effect Of Biological Enzymatic Treatment On the Surface Colo...mentioning

confidence: 99%

Study on the Characterization of Physical, Mechanical, and Mildew Resistance Properties of Enzymatically Treated Bamboo Fiber-Reinforced Polypropylene Composites

Meng,

Hu,

Liu

et al. 2023

Forests

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The enhancement of the physical and mechanical properties and the anti-mildew performance of wood–plastic composites are of great significance for broadening their application field. In this research, bamboo fibers underwent treatments with safe, environmentally friendly bio-enzymes. Subsequently, a bamboo–plastic composite (BPC) was developed using the modified bamboo fibers and polyethylene. The effects of biological enzymatic treatments on the surface free energy, the chemical composition of the bamboo fibers, water resistance, thermal stability, bending performance, impact performance, and anti-mildew performance of the BPC samples were analyzed. This study revealed that treating bamboo powder with bio-enzymes (xylanase, lipase, laccase, pectinase, hemicellulase, or amylase) decreased the surface free energy and the polar components of the bamboo fibers while improving the surface O/C atomic ratio of the bamboo fibers. These enzyme treatments enhanced the water resistance, bending performance, and anti-mildew performance of the BPC samples. However, on the whole, the thermal stability of the composites decreased. Particularly, after hemicellulase treatment, the composites had the lowest water absorption, reflecting a decrease of 68.25% compared to the control group. With xylanase modification, the 24 h water absorption thickness swelling rate of the composites was the lowest, reflecting a decrease of 71.27% compared to the control group. After pectinase modification, the static bending strength and elastic modulus of the prepared composites were the highest, with an increase of 15.45% and 13.31%, respectively, compared to the unmodified group. After xylanase modification, the composites exhibited the best anti-mildew effect, with an anti-mold effectiveness of 74.67%. In conclusion, bio-enzyme treatments can enhance the physical and mechanical properties and anti-mildew performance of BPCs. This research provides a theoretical foundation for the preparation of high-performance wood–plastic composites.

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“…Oil thermal treatment is considered to be an effective industrial modification method for improving the dimensional stability, mildew resistance and durability of bamboo and wood [ 10 , 11 , 12 ]. Compared with thermal treatment in steam [ 13 , 14 ] or a nitrogen atmosphere [ 15 ], oil thermal treatment can protect wood or bamboo from mold and fungi decay as well as prevent moisture access to its cell walls in the long term, as oil is not only a heat transfer medium but also an excellent modifier. Oil had been used as protective surface coating for over thousands years.…”

Section: Introductionmentioning

confidence: 99%

Tung Oil Thermal Treatment Improves the Visual Effects of Moso Bamboo Materials

Tang

Fei²,

Song³

et al. 2022

Polymers

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Color is one of the most important characteristics of a material’s appearance, which affects the additional value of bamboo and psychological feelings of users. Previous studies have shown that the dimensional stability, mildew resistance and durability of bamboo were improved after tung oil thermal treatment. In this study, the effects of tung oil thermal treatment on bamboo color at different temperatures and durations of time were investigated. The results show that the lightness (L*) of bamboo decreased as the tung oil temperature or duration of time increased. The red–green coordinates (a*) and color saturation (C*) of bamboo were gradually increased as the tung oil temperature rose from 23 °C to 160 °C, while the a* and C* were gradually decreased when the temperature continued to rise from 160 °C to 200 °C. There was no significant difference in the yellow–blue coordinates (b*) of bamboo when the duration was prolonged from 0.5 h to 3 h with tung oil thermal treatment at 140 °C. Eye movement data show that the popularity of bamboo furniture was significantly improved at 23–100 °C and slightly improved at 160–180 °C with tung oil treatment. Therefore, tung oil thermal treatment plays a positive role in improving visual effects and additional value of bamboo.

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Color changes of ash wood (Fraxinus excelsior L.) caused by thermal modification in air and steam

Cited by 3 publications

References 10 publications

Surface Characteristics of Thermally Modified Bamboo Fibers and Its Utilization Potential for Bamboo Plastic Composites

Surface Characteristics of Thermally Modified Bamboo Fibers and Its Utilization Potential for Bamboo Plastic Composites

Study on the Characterization of Physical, Mechanical, and Mildew Resistance Properties of Enzymatically Treated Bamboo Fiber-Reinforced Polypropylene Composites

Tung Oil Thermal Treatment Improves the Visual Effects of Moso Bamboo Materials

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