Effects of extracts on the colour of thermally modified Populus tomentosa Carr.

Bi, Zhenju; Yuan, Jin; Morrell, Jeffrey J.; Li, Yan

doi:10.1007/s00226-021-01304-7

Cited by 8 publications

(3 citation statements)

References 25 publications

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“…The Q structure is beneficial to UV absorption, while HQ has a stronger antioxidant ability. Both Q and HQ structures are the main chromophore and autochrome of OL-P . Therefore, the color change of OL may confirm the photooxidation process of phenolic hydroxyl and methoxyl groups.…”

Section: Resultsmentioning

confidence: 96%

“…The Q structure is beneficial to UV absorption, while HQ has a stronger antioxidant ability. Both Q and HQ structures are the main chromophore and autochrome of OL-P. 46 Therefore, the color change of OL may confirm the photooxidation process of phenolic hydroxyl and methoxyl groups. On the other hand, the radical scavenging ability and the SPF value of OL-P at different irradiation times were measured, with the aim to explore the influence of generation and transformation of SQ on UV-blocking and antioxidant capacity of OL-P.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Long-Acting Ultraviolet-Blocking Mechanism of Lignin: Generation and Transformation of Semiquinone Radicals

Qian

Zhang

et al. 2022

ACS Sustainable Chem. Eng.

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The natural inspired ultraviolet (UV)-absorbing function of lignin has been widely used in cosmetics and photothermal materials; however, its long-acting UV-blocking mechanism is still unclear. Herein, three organosolv lignins (OLs) were extracted from different botanical resources under mild conditions. These OLs preserved the native structure of lignin, and the best one was chosen to investigate the long-acting UV-blocking mechanism of lignin from the perspective of radicals. Results showed that 136% fresh semiquinone (SQ) radicals were formed when OL was irradiated under UV light for 4 h, and beyond half of these newly generated radicals were readily preserved after withdrawing UV irradiation. The generation and reduction of SQ in OL exhibited good photoresponsivity and cyclic stability, indicating that there was an SQ-based hydroquinone/quinone dynamic transformation. After 1 h of irradiation, the radical and phenolic hydroxyl contents in OL and the sun protection factor of an OL-based sunscreen increased by 110, 10, and 61%, respectively. After 12 h of irradiation, the antioxidant property of OL only weakened a little, while the sunscreen performance was still better than its initial state. The color of OL darkened at the initial time and then turned white gradually. This research paves the way to understanding the long-term UV-blocking mechanism and application of biomass lignin.

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Section: Resultsmentioning

confidence: 96%

Section: ■ Results and Discussionmentioning

confidence: 99%

Long-Acting Ultraviolet-Blocking Mechanism of Lignin: Generation and Transformation of Semiquinone Radicals

Qian

Zhang

et al. 2022

ACS Sustainable Chem. Eng.

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“…Acetone extract with strongest antifungal activity had the signi cant effect on the color of thermally modi ed poplar wood in our previous study, and it was selected as the extraction solvent (Bi et al, 2022 and2021b). Some studies also indicated that wood extracts extracted with solvents with electrical constants between 4 and 6 have strong antifungal activity and relatively rich chromogenic and auxochrome (Mahlo et al 2010;Candelier et al 2020).…”

Section: Preparation Of Thermally Modi Ed Wood and Extractionmentioning

confidence: 96%

Effects of extracts on color, dimensional stability, and decay resistance of thermally modified wood

Bi,

Zhou,

Chen

et al. 2023

Eur. J. Wood Prod.

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Thermal modi cation can enhance the color as well as improve the dimensional stability and decay resistance of wood without the use of chemical modi er, but the impact of extracts from thermally modi ed wood (TMW) on performance remains unclear. In order to utilize extracts to regulate the properties of the TMW or prepare the imitate TWM without mechanical loss, the effects of TMW acetone extracts on the color, dimensional stability, and decay resistance of TMW were investigated. The 180°C, 200°C and 220°C thermally modi ed spruce (Picea asperata Mast.) and poplar (Populus tomentosa Carr.)with or without acetone extract were used for CIELab system, anti-swelling e ciency(ASE), and decay resistance test. Fourier infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to characterize extracted and unextracted TMW. The results indicated that the extract showed positive effects on the color, dimensional stability (220°C), and decay resistance of TMW, and this effect weakened with the increase of temperature. The brightness difference (∆L*) and the total color difference (∆E*) of the TMW were reduced due to the removal of the extract, and the wood thermally modi ed at 180°C was the most signi cant. The removal of the extract will lead to the improvement of the dimensional stability of the TMW at 180°C and 200°C and the reduction of the TMW at 220°C. The decay resistance of wood thermally modi ed at 180°C, 200°C, and 220°C decreased after extraction, and was most signi cant at 180°C. The antifungal activity of the extract was related to the production of vanillin, isovanillic acid, syringic acid and syringaldehyde. Extract from TMW played an important role in the properties of TMW, and can be used to adjust its properties or as a natural wood modi er.

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Effect of applied standard wood machining fluid on colour and chemical composition of the machined wood surface

Chuchala,

Sommer,

Orlowski

et al. 2023

Eur. J. Wood Prod.

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Appropriate monitoring of wood machining processes is a key issue to ensure the expected quality of the processed wood, expected efficiency and minimize energy consumption of production processes. A new trend is the design of environmentally friendly machining fluids. In this paper, as a preliminary study in this field, the effect of applied standard wood machining fluid on changes in the colour and chemical composition of the machined wood surface is presented. Scots pine wood (Pinus sylvestris L.) was used for this research. Colour measurements were carried out based on the three-axis CIELab system test in time intervals and coefficients such as: colour chroma (Cab*), colour saturation (Sab*), colour hue (h°), and total colour changes (ΔE*). Changes in chemical composition were analysed on the Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR FT-IR). The results confirmed that standard machining fluids cause a significant change in the colour of the treated pine surface, which decreases over time but is still present even after 24 h. For the spectral analysis, no chemical changes were observed between the machining fluid and the wood. However, the fluid particles remained in the wood after 24 h. In order to reduce the effect of the machining fluid on the colour of the wood, its composition should be changed to allow and/or accelerate the evaporation of their components from the treated wood surface.

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Effects of extracts on the colour of thermally modified Populus tomentosa Carr.

Cited by 8 publications

References 25 publications

Long-Acting Ultraviolet-Blocking Mechanism of Lignin: Generation and Transformation of Semiquinone Radicals

Long-Acting Ultraviolet-Blocking Mechanism of Lignin: Generation and Transformation of Semiquinone Radicals

Effects of extracts on color, dimensional stability, and decay resistance of thermally modified wood

Effect of applied standard wood machining fluid on colour and chemical composition of the machined wood surface

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