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Journal articles on the topic 'Acetylated lignins'

Author: Grafiati
Published: 4 June 2021
Last updated: 17 February 2022

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1

Pu, Yunqiao, and Arthur J. Ragauskas. "Structural analysis of acetylated hardwood lignins and their photoyellowing properties." Canadian Journal of Chemistry 83, no. 12 (December 1, 2005): 2132–39. http://dx.doi.org/10.1139/v05-231.

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Lignin was isolated from aspen bleached chemithermomechanical pulp by employing a mild acid hydrolysis procedure, and the extracted material was acetylated with acetic anhydride. Nuclear magnetic resonance analyses indicated that the relative ease of acetylating lignin hydroxyl groups was phenolic >> γ-side chain > α-side chain. Non-acetylated and acetylated lignins were impregnated onto cellulosic test sheets, and the photo-behavior of the lignins was examined under irradiation with two light sources, a fluorescent lamp and a black lamp. Optical reflective studies indicated acetylation efficiently inhibited the photodiscoloration of aspen bleached chemithermomechanical pulp lignin under visible and near-UV light irradiation. The photostability of the lignin was correlated to the extent of lignin acetylation. The observed photo-stabilization of acetylated lignin during light irradiation was attributed to the acetylation of phenoxy and aliphatic hydroxyl groups in lignin.Key words: green chemistry, hardwood lignin, acetylation, photo-stabilization, photoyellowing, NMR.
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2

Marchand, Guillaume, Claude A. Calliste, René M. Williams, Charlotte McLure, Stéphanie Leroy-Lhez, and Nicolas Villandier. "Acetylated Lignins: A Potential Bio-Sourced Photosensitizer." ChemistrySelect 3, no. 20 (May 28, 2018): 5512–16. http://dx.doi.org/10.1002/slct.201801039.

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3

Ando, Daisuke, Fumiaki Nakatsubo, and Hiroyuki Yano. "Thermal stability of lignin in ground pulp (GP) and the effect of lignin modification on GP’s thermal stability: TGA experiments with dimeric lignin model compounds and milled wood lignins." Holzforschung 73, no. 5 (May 27, 2019): 493–99. http://dx.doi.org/10.1515/hf-2018-0137.

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Abstract For ground pulp (GP) utilization in wood fiber composites as reinforced material, its thermal behavior is relevant. The contribution of lignin to thermal performance of GP from Pinus densiflora was the focus of the present study. Dimeric lignin model compounds and isolated milled wood lignins (MWLs) from three sources were submitted for thermogravimetric analysis (TGA). The temperatures leading to 1% weight loss (T per 1% WL) for the material were determined. The thermal stability of β-O-4 models was the lowest. Among the MWLs, the abaca MWL with its high β-O-4 content was the least thermostable. An acetylated nonphenolic β-O-4 lignin model compound showed that acetylation improves the thermal stability of this type of dimeric models. The acetylation of benzylic OH groups in β-O-4 linkages is especially relevant for the thermal resistance, which was also shown based on pre-acetylated benzylic OH groups in the GP before the total acetylation.
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4

Marchand, Guillaume, Gabin Fabre, Nidia Maldonado-Carmona, Nicolas Villandier, and Stéphanie Leroy-Lhez. "Acetylated lignin nanoparticles as a possible vehicle for photosensitizing molecules." Nanoscale Advances 2, no. 12 (2020): 5648–58. http://dx.doi.org/10.1039/d0na00615g.

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5

Rotondo, Felipe, Rodrigo Coniglio, Leandro Cantera, Ignacio Di Pascua, Leonardo Clavijo, and Andrés Dieste. "Lignin-based coatings for controlled P-release fertilizer consisting of granulated simple superphosphate." Holzforschung 72, no. 8 (July 26, 2018): 637–43. http://dx.doi.org/10.1515/hf-2017-0176.

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AbstractA novel lignin-based slow release fertilizer with low environmental impact has been developed. More precisely, a granulated simple superphosphate fertilizer, consisting of calcium phosphate monobasic [Ca(H2PO4)2·H2O] and gypsum (CaSO4·2H2O) was coated with modified kraft lignins and the diffusion of phosphorus was observed as a function of time. The lignin was hydroxymethylated with formaldehyde and subsequently cross-linked with phenol-formaldehyde resin resulting in HML-PF as coating. Moreover, coating films were prepared from a mixture of acetylated lignin (Lac) and acetylated cellulose (Cellac). Both coatings show similar permeability to calcium phosphate and controlled effectively the P-release, particularly at the initial stages of the experiment. The P-release was linear in the decay phase but there is no lag time in the process. A significant P amount was not released from the particles coated with HML-PF, i.e. 80–50% remained irreversible bound, depending on the coating formulation. The maximum fractional P-release varied among the different coatings tested. Phosphorus is partly retained inside the slightly soluble calcium sulfate matrix.
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6

Amer, Hassan, Vebi Mimini, Dominik Schild, Uwe Rinner, Markus Bacher, Antje Potthast, and Thomas Rosenau. "Gram-scale economical synthesis of trans-coniferyl alcohol and its corresponding thiol." Holzforschung 74, no. 2 (February 25, 2020): 197–202. http://dx.doi.org/10.1515/hf-2018-0297.

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AbstractConiferyl alcohol is considered to be a potent antioxidant and a precursor of several bioactive products. In addition, it is a frequently used as a model compound in lignin chemistry. Coniferyl thiol is used analogously to study the sulfur chemistry in technical lignins. Coniferyl alcohol was synthesized in a large scale from commercially available ferulic acid by a mixed anhydride reduction method which affords high yields (84%) under very mild conditions and allows using sodium borohydride. The nucleophilic substitution of 4-O-acetylated coniferyl alcohol (3) with thioacetic acid in the presence of dimethylformamide (DMF) dineopentylacetal afforded 4-O-acetylated coniferyl thioacetate (5) in a 70% yield, which, in a 72% yield, was deprotected to the respective thiol (6). Both coniferyl alcohol and coniferyl thiol were comprehensively analytically characterized [one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy]. The presented approach renders the two model substances readily available on a gram scale and according to low-risk, environmentally compatible protocols.
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7

del Río, José C., Jorge Rencoret, Gisela Marques, Ana Gutiérrez, David Ibarra, J. Ignacio Santos, Jesús Jiménez-Barbero, Liming Zhang, and Ángel T. Martínez. "Highly Acylated (Acetylated and/orp-Coumaroylated) Native Lignins from Diverse Herbaceous Plants." Journal of Agricultural and Food Chemistry 56, no. 20 (October 22, 2008): 9525–34. http://dx.doi.org/10.1021/jf800806h.

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8

Wang, Linping, Kengo Shigetomi, Keiichi Koda, Aori Gele, and Yasumitsu Uraki. "A branched structure provides kraft lignins a denser morphology and a high molar mass for a given hydrodynamic radius." Holzforschung 74, no. 6 (April 1, 2020): 551–58. http://dx.doi.org/10.1515/hf-2019-0292.

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AbstractSize exclusion chromatography with multi-angle laser light-scattering detectors was applied for acetylated softwood and hardwood kraft lignins (Ac-SKL and Ac-HKL) and 8-O-4′ type of linear polymeric lignin model (Ac-M-8O4′) to compare their swelling behaviors. The plot of molar mass (MM) vs. retention time for Ac-M-8O4′ was similar to that of polystyrene, which revealed that Ac-M-8O4′ exhibited swelling behavior that was similar to that of polystyrene. However, the MM values of both Ac-KLs were larger than those of polystyrene standards at any retention time. This difference indicated that both Ac-KLs had a more compact structure than those of polystyrene and Ac-M-8O4′. One hypothesis is that the larger MM of both Ac-KLs stems from their branched structures. To verify this hypothesis, the frequency of 5-5′ interunit linkage in lignin samples was determined by 1H NMR after nitrobenzene oxidation. A linear relationship between MM and 5-5′ abundance was observed in the high MM region.
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9

Wen, Jia-Long, Shao-Long Sun, Bai-Liang Xue, and Run-Cang Sun. "Quantitative structural characterization of the lignins from the stem and pith of bamboo (Phyllostachys pubescens)." Holzforschung 67, no. 6 (August 1, 2013): 613–27. http://dx.doi.org/10.1515/hf-2012-0162.

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Abstract Milled wood lignins (MWL) were isolated from the stem (MWLS) and pith (MWLP) of bamboo (Phyllostachys pubescens). The nonacetylated and acetylated bamboo MWLs were investigated by Fourier transform infrared, quantitative 13C-nuclear magnetic resonance (NMR), 2D heteronuclear single quantum coherence (HSQC) NMR, and 31P-NMR spectroscopy. The MWL consists of p-hydroxyphenyl (1–2%), guaiacyl (21–31%), and syringyl (67–78%) units associated with p-coumarates and ferulates. A modified quantitative 13C-NMR and 2D-HSQC analysis has demonstrated that the predominant intermonomeric linkages are of the type β-O-4 (45–49 per 100 C9 units, i.e., per C900) along with small amounts of other structural units such as resinols (3.6–7.4 per C900), tetrahydrofuran (2.0–2.3 per C900), phenylcoumaran (2.8–4.5 per C900), spirodienones (1.3–2.3 per C900), and α,β-diaryl ethers (2.8–2.9 per C900). MWLP contained more p-coumarates than MWLS. The various degrees of γ-acylation (17–27%) were positively associated with S/G ratios in the lignins; however, γ-acylation was inversely correlated to the ratio between β-β and β-O-4 side chains in these lignin fractions. Moreover, a flavonoid compound (tricin) was also detected in the MWLS but not in MWLP. The two MWLs are very similar in terms of molecular weights and the contents of OHphen and OHaliph.
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10

Lundquist, Knut, Sverker von Unge, Martin Nilsson, Curt R. Enzell, Jan-Eric Berg, and Anders Ljungqvist. "NMR Studies of Lignins. 8. Examination of Pyridine-d5 Solutions of Acetylated Lignins from Birch and Spruce by 1H NMR Spectroscopy." Acta Chemica Scandinavica 40b (1986): 791–97. http://dx.doi.org/10.3891/acta.chem.scand.40b-0791.

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11

Lagerquist, Lucas, Andrey Pranovich, Ivan Sumerskii, Sebastian von Schoultz, Lari Vähäsalo, Stefan Willför, and Patrik Eklund. "Structural and Thermal Analysis of Softwood Lignins from a Pressurized Hot Water Extraction Biorefinery Process and Modified Derivatives." Molecules 24, no. 2 (January 18, 2019): 335. http://dx.doi.org/10.3390/molecules24020335.

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In this work we have analyzed the pine and spruce softwood lignin fraction recovered from a novel pressurized hot water extraction pilot process. The lignin structure was characterized using multiple NMR techniques and the thermal properties were analyzed using thermal gravimetric analysis. Acetylated and selectively methylated derivatives were prepared, and their structure and properties were analyzed and compared to the unmodified lignin. The lignin had relatively high molar weight and low PDI values and even less polydisperse fractions could be obtained by fractionation based on solubility in i-PrOH. Condensation, especially at the 5-position, was detected in this sulphur-free technical lignin, which had been enriched with carbon compared to the milled wood lignin (MWL) sample of the same wood chips. An increase in phenolic and carboxylic groups was also detected, which makes the lignin accessible to chemical modification. The lignin was determined to be thermally stable up to (273–302 °C) based on its Tdst 95% value. Due to the thermal stability, low polydispersity, and possibility to tailor its chemical properties by modification of its hydroxyl groups, possible application areas for the lignin could be in polymeric blends, composites or in resins.
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12

Clauss, Manuel M., Dianne L. Weldin, Erik Frank, Elisabeth Giebel, and Michael R. Buchmeiser. "Size-Exclusion Chromatography and Aggregation Studies of Acetylated Lignins in N,N -Dimethylacetamide in the Presence of Salts." Macromolecular Chemistry and Physics 216, no. 20 (September 1, 2015): 2012–19. http://dx.doi.org/10.1002/macp.201500222.

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13

San Feliciano, Arturo, Jose M. Miguel Del Corral, Marina Gordaliza, and M. Angeles Castro. "Acetylated lignans from Juniperus sabina." Phytochemistry 28, no. 2 (January 1989): 659–60. http://dx.doi.org/10.1016/0031-9422(89)80081-0.

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14

Merkle, Gerhard, Sabine Auerbach, Walther Burchard, Albert Lindner, and Gerd Wegener. "Light scattering of acetylated lignin." Journal of Applied Polymer Science 45, no. 3 (May 25, 1992): 407–15. http://dx.doi.org/10.1002/app.1992.070450305.

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15

Del Río, José C., Gisela Marques, Jorge Rencoret, Ángel T. Martínez, and Ana Gutiérrez. "Occurrence of Naturally Acetylated Lignin Units." Journal of Agricultural and Food Chemistry 55, no. 14 (July 2007): 5461–68. http://dx.doi.org/10.1021/jf0705264.

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16

Chen, Tianying, Zhiwen Li, Xueming Zhang, Douyong Min, Yuying Wu, Jialong Wen, and Tongqi Yuan. "Effects of Hydrothermal Pretreatment on the Structural Characteristics of Organosolv Lignin from Triarrhena lutarioriparia." Polymers 10, no. 10 (October 16, 2018): 1157. http://dx.doi.org/10.3390/polym10101157.

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The effects of hydrothermal pretreatment (170–180 °C, 30–60 min) on the structural characteristics of enzymatic and extracted lignin from Triarrhena lutarioriparia (TL) during the integrated delignification process have been comprehensively investigated. Ion chromatography and NMR characterization showed that liquid products after mild hydrothermal process (170 °C, 30 min) were mainly composed of xylooligosaccharide (XOS) with different degrees of polymerization (DP ≥ 2). In addition, the structural changes of lignin during hydrothermal pretreatment and organic acid delignification process have been demonstrated by quantitative 2D heteronuclear single quantum coherence (2D-HSQC) and 31P-NMR techniques. Results showed that the structural changes of lignin (e.g., cleavage of β-O-4 linkages) induced by the hydrothermal pretreatment will facilitate the subsequent organic acid delignification process, and acetylated lignin could be obtained with a considerable yield, which can be used in lignin-based composite and candidate feedstock for catalytic upgrading of lignin. In short, the proposed process facilitates the producing of XOS and acetylated lignin for lignin valorization.
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17

Qian, Yong, Yonghong Deng, Hao Li, and Xueqing Qiu. "Reaction-Free Lignin Whitening via a Self-Assembly of Acetylated Lignin." Industrial & Engineering Chemistry Research 53, no. 24 (June 4, 2014): 10024–28. http://dx.doi.org/10.1021/ie5010338.

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18

Abid, Amine, Fatima Charrier El Bouhtoury, and Slimane Gabsi. "Recovery of Residues from Olive Industry: Characterization of Simple and Acetylated Lignin." Annales de Chimie - Science des Matériaux 44, no. 5 (October 31, 2020): 327–32. http://dx.doi.org/10.18280/acsm.440504.

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Lignin is a renewable material obtained in large quantities as a by-product of the olive industry. In this context, this study aims to examine lignin as macro-monomers in the synthesis of rigid polyurethane foam after chemical modification. Indeed, the lignin extracted from the olive residue is used by chemical treatment according to the organosolv process. Comparison by characterization of the single isolated lignin and the acetylated lignin according to the physicochemical analysisTGA, DSC, FTIR, C-13 NMR, 1-H NMR, and molar mass distribution (sec) shows its value as biomass capable of being transformed into polyol afterchemical modification. acetylation increases the weight and the number of molar masses by 25-50% was also determined. Acetylation has a greater effect on the short chains which are probably richer in free phenolic groups. Mass distribution analyzes reveal a relatively high molar mass in organosolv lignin moreover, polydispersity values are very high (20 >> 1). The characterization of spent olive cake reflects the interest of using this biomass as a source of renewable energy for the production of industrial polymers.
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19

Krisdianto, Krisdianto, Peter Vinden, and Simon Prezwloka. "Accelerated Weathering Performances of Furfurylated and Acetylated Bamboo Sheets." Wood Research Journal 9, no. 2 (May 13, 2020): 60–68. http://dx.doi.org/10.51850/wrj.2018.9.2.60-68.

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Bamboo material is a potential wood substitute given that its physical and mechanical properties are comparable with those of wood. As lignocellulose material, bamboo is also degraded for use outdoor. Two significant chemical modification for wood which may work for bamboo material are acetylation and furfurylation. This paper evaluates the weathering performance of furfurylated and acetylated bamboo sheets. Parameters studied include colour changes and contact angle after accelerated weathering process at QUV chamber. The result shows that the total colour differences ( E*) of furfurylation is higher than non-modified strips, while colour differences of acetylated bamboo strips are less than nonmodified strips. To summarize, chemically modified Sheets turn grey after weathering. Slowing of lignin photo-degradation by acetylation is attributed to the acetyl groups, which limits the degradation of lignin. Treating bamboo sheets with acetic anhydride and furfuryl alcohol was found to be effective in protecting bamboo from absorbing water during weather exposure.
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20

Maldonado-Carmona, Nidia, Tan-Sothea Ouk, Nicolas Villandier, Claude Alain Calliste, Mário J. F. Calvete, Mariette M. Pereira, and Stéphanie Leroy-Lhez. "Photophysical and Antibacterial Properties of Porphyrins Encapsulated inside Acetylated Lignin Nanoparticles." Antibiotics 10, no. 5 (April 30, 2021): 513. http://dx.doi.org/10.3390/antibiotics10050513.

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Lignin has recently attracted the attention of the scientific community, as a suitable raw material for biomedical applications. In this work, acetylated lignin was used to encapsulate five different porphyrins, aiming to preserve their photophysical properties, and for further use as antibacterial treatment. The obtained nanoparticles were physically characterized, through dynamic light scattering size measurement, polydispersity index and zeta potential values. Additionally, the photophysical properties of the nanoparticles, namely UV-vis absorption, fluorescence emission, singlet oxygen production and photobleaching, were compared with those of the free porphyrins. It was found that all the porphyrins were susceptible to encapsulation, with an observed decrease in their fluorescence quantum yield and singlet oxygen production. These nanoparticles were able to exert an effective photodynamic bactericide effect (blue-LED light, 450–460 nm, 15 J/cm2) on Staphylococcus aureus and Escherichia coli. Furthermore, it was achieved a photodynamic bactericidal activity on an encapsulated lipophillic porphyrin, where the free porphyrin failed to diminish the bacterial survival. In this work it was demonstrated that acetylated lignin encapsulation works as a universal, cheap and green material for the delivery of porphyrins, while preserving their photophysical properties.
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Nakanishi, Simone Coelho, Adilson Roberto Gonçalves, George J. M. Rocha, Maria de Lourdes Ballinas, and Guillermo Gonzalez. "Use of Lignocellulosic Components of Sugarcane Bagasse to Obtaining Polymeric Composite Membranes." Advanced Materials Research 123-125 (August 2010): 1203–6. http://dx.doi.org/10.4028/www.scientific.net/amr.123-125.1203.

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Currently, several research groups and industries are studying applications for the residues from agribusiness, other than burning them. Thinking about a better use for the sugarcane bagasse, this study aims to obtain membranes of cellulose acetate composite with oxidized lignin, both isolated from sugarcane bagasse. Thus, we obtain a product with higher commercial value, from a natural fiber residue from agribusiness, which has applications in water and effluent treatment, and further contributes to the maintenance of the environment. Macromolecular components of bagasse (hemicellulose, cellulose and lignin) were separated by applying a steam explosion pre-treatment for the removal of the hemicellulose, a basic treatment with NaOH to separate the lignin and obtain crude cellulose pulp. This pulp was bleached and acetylated, and subsequently membranes of cellulose acetate were synthesized, incorporating oxidized lignin to these membranes in order to increase the metal retention capacity of these membranes. The acetylated material was analyzed by IR, confirming acetylation. Degree of substitution was determined by volumetry, yielding a value of 1.7, featuring a diacetate. The synthesized membranes were analyzed by SEM, showing a dense structure. Tests were conducted to evaluate metal retention, and the average capacity of removal was 15% Cu+2 in steady-state experiments. Retention capacity in membranes is 20 times higher than the retention using chromatographic columns separation.
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22

Hansmann, Christian, Manfred Schwanninger, Barbara Stefke, Barbara Hinterstoisser, and Wolfgang Gindl. "UV-microscopic analysis of acetylated spruce and birch cell walls." Holzforschung 58, no. 5 (August 1, 2004): 483–88. http://dx.doi.org/10.1515/hf.2004.073.

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Abstract Spruce and birch earlywood was acetylated to different weight percent gains using three different acetylation procedures. The absorbance spectra of secondary cell wall and compound cell corner middle lamella were determined by means of UV microscopy. Analysis of the spectra showed that the characteristic lignin absorbance peak in the UV spectrum of wood around 280 nm shifted to shorter wavelengths in acetylated samples. A distinct relationship between achieved weight percent gains after acetylation and observed spectral shifts could be established revealing a certain potential to measure acetylation on a cellular level by means of UV microscopy.
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23

Zhang, Meng, and Amod A. Ogale. "Carbon fibers from dry-spinning of acetylated softwood kraft lignin." Carbon 69 (April 2014): 626–29. http://dx.doi.org/10.1016/j.carbon.2013.12.015.

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24

Pu, Yunqiao, Sean Anderson, Lucian Lucia, and Arthur J. Ragauskas. "Investigation of the photo-oxidative chemistry of acetylated softwood lignin." Journal of Photochemistry and Photobiology A: Chemistry 163, no. 1-2 (April 2004): 215–21. http://dx.doi.org/10.1016/j.jphotochem.2003.11.009.

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25

Suzuki, Shiori, Shimon Kurachi, Naoki Wada, and Kenji Takahashi. "Selective Modification of Aliphatic Hydroxy Groups in Lignin Using Ionic Liquid." Catalysts 11, no. 1 (January 15, 2021): 120. http://dx.doi.org/10.3390/catal11010120.

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A facile, sustainable method for the selective modification of aliphatic hydroxy (R–OH) groups in Kraft lignin was developed using an ionic liquid, 1-ethyl-3-methylimidazolium acetate (EmimOAc), as a solvent and catalyst. Selective R–OH modification was achieved by a one-pot, two-step homogeneous reaction: (i) acetylation of R–OH and aromatic OH (Ar–OH) groups with isopropenyl acetate (IPAc) as an acyl donor and (ii) subsequent selective deacetylation of the generated aromatic acetyl (Ar–OAc) groups. In step (i), IPAc reacts rapidly with Ar–OH but slowly with R–OH. The generated Ar–OAc is gradually deacetylated by heating in EmimOAc, whereas the aliphatic acetyl (R–OAc) groups are chemically stable. In step (ii), all R–OH is acetylated by IPAc and Ar–OAc which is a better acyl donor than IPAc, contributing to the rapid acetylation of the remaining R–OH, and selective deacetylation of the residual Ar–OAc is completed by adding a tiny amount of water as a proton source. This two-step reaction resulted in selective R–OH modification (>99%) in Kraft lignin with the remaining being almost all Ar–OH groups (93%). Selectively modified Kraft lignin was obtained with an acceptably high isolated yield (85%) and repeatability (N = 3). Furthermore, despite the lower substitution degree, it exhibited solubility in common solvents, heat-meltability, and thermal stability comparable to completely acetylated Kraft lignin.
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Fodor, Fanni, and Róbert Németh. "Testing the Photostability of Acetylated and Boiled Linseed Oil-coated Common Hornbeam (Carpinus betulus L.) Wood." Acta Silvatica et Lignaria Hungarica 13, no. 1 (June 1, 2017): 81–94. http://dx.doi.org/10.1515/aslh-2017-0006.

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AbstractIn this study, the effect of acetylation and coating with boiled linseed oil was evaluated concerning the photodegradation of common hornbeam wood (Carpinus betulusL.). To measure colour stability, a 10-month-long outdoor weather resistance test without soil contact was performed as well as artificial aging using a 200 hour mercury-vapour lamp irradiation test. The measurements were done on hornbeam, acetylated hornbeam, boiled linseed oil-treated hornbeam, and acetylated and boiled linseed oil-treated hornbeam samples. The control and treated samples’ colour change was determined by comparing them to the original colour in all cases. The photodegradation process was examined with Fourier Transform Infrared (FTIR) spectra. Acetylated hornbeam was less prone to crack, but the modification did not hinder the fading and greying caused by UV irradiation. Coating the samples with boiled linseed oil decreased the rate of colour change and cracking. The photodegradation of lignin was confirmed by the FTIR spectra.
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27

Yang, Tiantian, Emil Engelund Thybring, Maria Fredriksson, Erni Ma, Jinzhen Cao, Ramūnas Digaitis, and Lisbeth Garbrecht Thygesen. "Effects of Changes in Biopolymer Composition on Moisture in Acetylated Wood." Forests 11, no. 7 (June 29, 2020): 719. http://dx.doi.org/10.3390/f11070719.

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To investigate the effects of changes in biopolymer composition on moisture in acetylated poplar wood (Populus euramericana Cv.), the acetylation of control wood was compared to the acetylation of wood with reduced hemicellulose or lignin content (about 9% reduction of total specimen dry weight in both cases). Time-domain nuclear magnetic resonance relaxometry of water-saturated wood gave spin–spin relaxation times (T2) of water populations, while deuteration in a sorption balance was used to characterize the hydroxyl accessibility of the wood cell walls. As expected, the acetylation of pyridine-swelled wood reduced hydroxyl accessibility and made the cell wall less accessible to water, resulting in a reduction of cell wall moisture content by about 24% compared with control wood. Hemicellulose loss per se increased the spin–spin relaxation time of cell wall water, while delignification had the opposite effect. The combined effect of hemicellulose removal and acetylation caused more than a 30% decrease of cell wall moisture content when compared with control wood. The acetylated and partially delignified wood cell walls contained higher cell wall moisture content than acetylated wood. An approximate theoretical calculation of hydroxyl accessibility for acetylated wood was in the low range, but it agreed rather well with the measured accessibility, while acetylated and partially hemicellulose-depleted and partially delignified wood for unknown reasons resulted in substantially lower hydroxyl accessibilities than the theoretical estimate.
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Pizzi, A., X. Zhou, P. Navarrete, C. Segovia, H. R. Mansouri, M. I. Placentia Pena, and F. Pichelin. "Enhancing water resistance of welded dowel wood joints by acetylated lignin." Journal of Adhesion Science and Technology 27, no. 3 (February 2013): 252–62. http://dx.doi.org/10.1080/01694243.2012.705512.

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29

Ralph, John. "1H NMR of acetylated β-ether/β-ether lignin model trimers." Magnetic Resonance in Chemistry 31, no. 4 (April 1993): 357–63. http://dx.doi.org/10.1002/mrc.1260310409.

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30

Jeong, Heonyoung, Jongshin Park, Sunghoon Kim, Jungmin Lee, and Jae Whan Cho. "Use of acetylated softwood kraft lignin as filler in synthetic polymers." Fibers and Polymers 13, no. 10 (December 2012): 1310–18. http://dx.doi.org/10.1007/s12221-012-1310-6.

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31

Jeong, Heonyoung, Jongshin Park, Sunghoon Kim, Jungmin Lee, Narang Ahn, and Hyun-gyoo Roh. "Preparation and characterization of thermoplastic polyurethanes using partially acetylated kraft lignin." Fibers and Polymers 14, no. 7 (July 2013): 1082–93. http://dx.doi.org/10.1007/s12221-013-1082-7.

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32

Roh, Hyun-gyoo, Sunghoon Kim, Jungmin Lee, and Jongshin Park. "Effect of Low-Temperature Pyrolysis on the Properties of Jute Fiber-Reinforced Acetylated Softwood Kraft Lignin-Based Thermoplastic Polyurethane." Polymers 10, no. 12 (December 3, 2018): 1338. http://dx.doi.org/10.3390/polym10121338.

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Short jute fiber-reinforced acetylated lignin-based thermoplastic polyurethane (JF reinforced ASKLTPU) was prepared and characterized as a short-fiber-reinforced elastomer with carbon-neutrality and biodegradability. The acetylated softwood kraft lignin-based thermoplastic polyurethane (ASKLTPU) was prepared with polyethylene glycol (PEG) as a soft segment. Short jute fiber was modified using low-temperature pyrolysis up to the temperatures of 200, 250, and 300 °C in order to remove non-cellulosic compounds of jute fibers for enhancing interfacial bonding and reducing hydrophilicity with the ASKLTPU matrix. JF-reinforced ASKLTPUs with fiber content from 5 to 30 wt % were prepared using a melt mixing method followed by hot-press molding at 160 °C. The JF-reinforced ASKLTPUs were characterized for their mechanical properties, dynamic mechanical properties, thermal transition behavior, thermal stability, water absorption, and fungal degradability. The increased interfacial bonding between JF and ASKLTPU using low-temperature pyrolysis was observed using scanning electron microscopy (SEM) and also proved via interfacial shear strength measured using a single-fiber pull-out test. The mechanical properties, thermal properties, and water absorption aspects of JF-reinforced ASKLTPU were affected by increased interfacial bonding and reduced hydrophilicity from low-temperature pyrolysis. In the case of the degradation test, the PEG component of ASKLPTU matrix highly affects degradation and deterioration.
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33

Qu, Chen, Takao Kishimoto, Shinjiro Ogita, Masahiro Hamada, and Noriyuki Nakajima. "Dissolution and acetylation of ball-milled birch (Betula platyphylla) and bamboo (Phyllostachys nigra) in the ionic liquid [Bmim]Cl for HSQC NMR analysis." Holzforschung 66, no. 5 (July 1, 2012): 607–14. http://dx.doi.org/10.1515/hf.2011.186.

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Abstract A method for nuclear magnetic resonance (NMR) characterization of whole cell wall components, including lignin, cellulose and hemicelluloses, was recently developed in our laboratory. The method described for fir (Abies sachalinensis) as a softwood consists of ball-milling of cell wall, dissolution in an ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]Cl), in situ acetylation, recovery of the material from the solution, and characterization of the product by 1H-13C correlation heteronuclear single quantum coherence (HSQC) NMR spectroscopy in dimethyl sulfoxide (DMSO)-d6. In the present paper, the performance of the method should be tested for a hardwood and a bamboo. Thus, Japanese white birch (Betula platyphylla) and hachiku bamboo (Phyllostachys nigra) have been investigated. Finely ball-milled birch and bamboo materials were completely dissolved in [Bmim]Cl at 100°C without severe chemical modification of the cell wall components. The dissolved cell walls were then subjected to in situ acetylation, and the ball-milled and fully acetylated cell walls were recovered from [Bmim]Cl. Longer ball-milling time was required for birch and bamboo cell walls, because of the lower solubility of acetylated birch and bamboo materials in DMSO-d6compared to the acetylated fir material. However, HSQC NMR experiments were successfully conducted, and the acetylated whole cell wall components in the birch and bamboo could be fully characterized. This method is applicable for the analysis of cell wall components of various plant biomasses without previous isolation. Further studies are necessary to improve the method.
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34

Wu, Adam, Jean Michel Lauzon, and Brian R. James. "Hydrogenolysis of a γ-Acetylated Lignin Model Compound with a Ruthenium–Xantphos Catalyst." Catalysis Letters 145, no. 2 (October 30, 2014): 511–18. http://dx.doi.org/10.1007/s10562-014-1401-7.

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35

Cavallo, Ema, Xiaoyan He, Francesca Luzi, Franco Dominici, Patricia Cerrutti, Celina Bernal, Maria Laura Foresti, Luigi Torre, and Debora Puglia. "UV Protective, Antioxidant, Antibacterial and Compostable Polylactic Acid Composites Containing Pristine and Chemically Modified Lignin Nanoparticles." Molecules 26, no. 1 (December 29, 2020): 126. http://dx.doi.org/10.3390/molecules26010126.

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Polylactic acid (PLA) films containing 1 wt % and 3 wt % of lignin nanoparticles (pristine (LNP), chemically modified with citric acid (caLNP) and acetylated (aLNP)) were prepared by extrusion and characterized in terms of their overall performance as food packaging materials. Morphological, mechanical, thermal, UV–Vis barrier, antioxidant and antibacterial properties were assayed; appropriate migration values in food simulants and disintegration in simulated composting conditions were also verified. The results obtained indicated that all lignin nanoparticles succeeded in conferring UV-blocking, antioxidant and antibacterial properties to the PLA films, especially at the higher filler loadings assayed. Chemical modification of the fillers partially reduced the UV protection and the antioxidant properties of the resulting composites, but it induced better nanoparticles dispersion, reduced aggregates size, enhanced ductility and improved aesthetic quality of the films through reduction of the characteristic dark color of lignin. Migration tests and disintegration assays of the nanocomposites in simulated composting conditions indicated that, irrespectively of their formulation, the multifunctional nanocomposite films prepared behaved similarly to neat PLA.
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36

Olaniran, Samuel Oluyinka, Cabane Etienne, Tobias Keplinger, Babatola Olufemi, and Markus Rüggeberg. "Mechanical behaviour of acetylated rubber wood subjected to artificial weathering." Holzforschung 73, no. 11 (October 25, 2019): 1005–16. http://dx.doi.org/10.1515/hf-2018-0274.

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Abstract Rubber wood utilization in Nigeria has become a viable alternative because of over-exploitation of more durable species. The use of rubber wood in its native form has some disadvantages including dimensional instability, low durability and susceptibility to weathering in outdoor uses. However, it may be improved through chemical modification such as acetylation. In this study, we revealed the effectiveness of acetylation on the protection of rubber wood against weathering in terms of weight loss (WL), colour change, lignin degradation, and mechanical properties. Acetylation was carried out using two different reaction times to achieve weight percent gains (WPG) of around 7% and 10%. Understanding of the effect of acetylation and subsequent weathering on mechanical properties was enabled by analysing wood chemistry with Fourier transform infrared (FTIR) analysis and Raman spectroscopy. The mechanical tests of weathered unmodified and acetylated rubber wood revealed a decrease of tensile stiffness of the unmodified samples as a function of weathering time, while stiffness was retained for the acetylated samples. Weathered unmodified samples showed a bi-phasic stress-strain pattern with a high strain at breakage indicating a slippage of fibres under stress due to degradation of the middle lamella. This was hardly visible for acetylated samples. Thus, acetylation was shown to be effective for protecting rubber wood used in outdoor conditions.
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37

Sander, C., and G. Koch. "Effects of Acetylation and Hydrothermal Treatment on Lignin as Revealed by Cellular UV-Spectroscopy in Norway Spruce (Picea abies [L.] Karst.)." Holzforschung 55, no. 2 (February 21, 2001): 193–98. http://dx.doi.org/10.1515/hf.2001.032.

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Summary The effect of two different wood modification treatments on the lignin of Norway spruce wood was studied by means of cellular UV-spectroscopy. The modification treatments chosen were acetylation using acetic anhydride and a two step hydrothermal treatment. Small cross sectional thin slides from the wood surface were taken and were subsequently analysed using a UV-micro-spectro-photometer. The modified samples were compared with a non-treated control sample. The results revealed changes in the absorption spectra of lignin after both modification treatments. Spectra of the compound middle lamella (CML) of acetylated wood revealed a decrease in the lignin-specific absorption maximum at 280nm, which is considered to be caused by superficial leaching of lignin due to acetylation. The retarding effect of acetylation on UV-degradation of wood is discussed. In hydrothermal-treated wood the 280nm maximum was increased within the S2 layer. This maximum remained almost unchanged in the CML while a lower maximum was observed at about 330nm. Changes in the chromophoric behaviour of lignin are probably caused by de-masking reactions within the S2 layer resulting from hydrolysis of carbohydrates and side chain reactions. Both treatments lead to a severe decrease in absorption at the lower end of the spectrum towards 250nm which is possibly attributed to changes or even splitting of biphenyls.
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38

Zhao, Li Hong, and Hong Jun Sun. "Comparative Study of Two Types of Alkali Lignin from Different Origin." Advanced Materials Research 299-300 (July 2011): 747–50. http://dx.doi.org/10.4028/www.scientific.net/amr.299-300.747.

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The physico-chemical characterization of two types of alkali lignin from different origin, namely L1 and L2, were studied by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectrometry (1H NMR) and gel permeation chromatography (GPC) analysis. FT-IR spectra show that they have the characteristics of absorption peaks of syringyl and guaiacyl. 1H NMR spectra indicate that acetylated L1 exhibits higher content of aromatic protons than L2, as the former is mainly composed by G units. L2 presents high quantities of methoxyl groups. GPC results show that L1 has much higher weight average than L2. They had similar functional groups, however, there were differences in the relative contents of functional groups.
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39

Lohr, Tracy L., Zhi Li, and Tobin J. Marks. "Selective Ether/Ester C–O Cleavage of an Acetylated Lignin Model via Tandem Catalysis." ACS Catalysis 5, no. 11 (October 26, 2015): 7004–7. http://dx.doi.org/10.1021/acscatal.5b01972.

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40

del Río, José C., Ana Gutiérrez, and Ángel T. Martínez. "Identifying acetylated lignin units in non-wood fibers using pyrolysis-gas chromatography/mass spectrometry." Rapid Communications in Mass Spectrometry 18, no. 11 (May 21, 2004): 1181–85. http://dx.doi.org/10.1002/rcm.1457.

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41

Windayani, Neneng, Lia Juliawaty, Euis Hakim, Komar Ruslan, and Yana Syah. "An Acetylated Triterpene Glycoside and Lignans from Phyllanthus myrtifolius and their Antibacterial Activities." Natural Products Journal 5, no. 3 (October 16, 2015): 152–57. http://dx.doi.org/10.2174/2210315505666150827213538.

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42

Mughal, M. Moeez, M. Wasim Akhtar, M. Moazam Baloch, Muddassir Ali Memon, Junaid Ali Syed, and Jong Seok Kim. "Effect of silanized sisal fiber on thermo-mechanical properties of reinforced epoxy composites." Journal of Composite Materials 54, no. 15 (November 28, 2019): 2037–50. http://dx.doi.org/10.1177/0021998319890660.

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An effective method was adopted to improve the thermo-mechanical properties of the epoxy composite by functionalization of the sisal fiber. Initially, a neat sisal fiber was acetylated with molar solution of acidic mixture (0.5:1 of HNO3:H2SO4) that removed the content of lignin and hemicellulose and increased the crystallinity of the sisal fiber. The acetylated sisal ( a-sisal) fiber was further treated with 3-aminpropyltriethoxy silane to graft the silanol moieties on sisal fiber. The functionalization of the sisal fiber with 3-aminpropyltriethoxy silane exhibits the strong interaction with epoxy, resulting in homogenous dispersion of the sisal fiber in epoxy. The composite possesses great enhancement in thermal and mechanical properties. The tensile strength in functionalized sisal epoxy composite ( CP-f-Sisal) was significantly enhanced up to 23% in comparison to non-functionalized sisal epoxy composite ( CP-n-Sisal) by adding 15 wt.% of the sisal fiber. In addition, the functionalized sisal epoxy composite ( CP-f-sisal) shows better thermal stability as compared to non-functionalized sisal epoxy composite ( CP-n-sisal). Similar results are attributed by investigating the kinetics of thermal stability parameters that include activation energy and integral procedure decomposition temperature.
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43

Chang, Shang-Tzen, and Hui-Ting Chang. "Inhibition of the Photodiscoloration of Wood by Butyrylation." Holzforschung 55, no. 3 (April 25, 2001): 255–59. http://dx.doi.org/10.1515/hf.2001.042.

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Summary The lightfastness of butyrylated China fir (Cunninghamia lanceolata var. lanceolata) and maple (Acer sp.) was evaluated in this study, and its effectiveness was compared with that of acetylated specimens. The color fading in acetylated China fir and maple woods was reduced to half that of untreated specimens, after a 24-day UV lightfastness test. The effectiveness of butyrylation on photodiscoloration prevention in wood was even more pronounced than that with acetylation. With an 18.57% weight percent gain, butyrylation remarkably inhibited the discoloration of wood following UV irradiation. Based on infrared spectral analysis, the lignin of both untreated and butyrylated woods deteriorated after exposure to UV light, but the holocellulose in butyrylated wood was more resistant to the UV light. Furthermore, results obtained from diffuse reflectance UV-VIS spectral analysis elucidated that the absorption of irradiated butyrylated wood, in comparison with that of the irradiated but untreated specimens, was lower in both UV light and visible light regions. It also revealed that the inhibition of photodiscoloration of wood by butyrylation was caused mainly by a significant reduction of chromophoric derivatives, such as quinoid compounds, formed on the wood surface.
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44

Rencoret, Jorge, José C. del Río, Ana Gutiérrez, Ángel T. Martínez, Shiming Li, Jim Parkås, and Knut Lundquist. "Origin of the acetylated structures present in white birch (Betula pendula Roth) milled wood lignin." Wood Science and Technology 46, no. 1-3 (April 2, 2011): 459–71. http://dx.doi.org/10.1007/s00226-011-0417-z.

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45

Xia, Liang, Xiaobao Li, Nan Pan, Hang Yu, and Eryu Wang. "Novel green and cost-effective preparation of acetylated lignin at high temperature without further separation." Materials Research Express 7, no. 11 (November 10, 2020): 115401. http://dx.doi.org/10.1088/2053-1591/abc652.

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46

Musa, Shadan, Oliver Richter, Matthias Balsam, Aron Kneer, and Stéphan Barbe. "Macroporous films from acetylated lignin and cellulose as precursors for smart coatings based on regenerated wood." European Journal of Wood and Wood Products 76, no. 4 (April 18, 2018): 1363–66. http://dx.doi.org/10.1007/s00107-018-1308-x.

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47

Altaner, Clemens, David C. Apperley, and Michael C. Jarvis. "Spatial relationships between polymers in Sitka spruce: Proton spin-diffusion studies." Holzforschung 60, no. 6 (November 1, 2006): 665–73. http://dx.doi.org/10.1515/hf.2006.112.

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Abstract The spatial arrangement of polymers in Sitka spruce (Picea sitchensis) was investigated by NMR proton spin-diffusion studies, supplemented by deuterium-exchange experiments monitored by FTIR spectroscopy. The FTIR spectra of earlywood sections after vapour-phase exchange with deuterium oxide showed that 43% of the hydroxyl groups were accessible to deuteration. This value is lower than predicted in the absence of aggregation of cellulose microfibrils into larger units, but greater than the predicted level of deuteration if 3.5-nm microfibrils surrounded by hemicellulose sheaths were aggregated into 4×4 arrays without space for deuterium oxide to penetrate between the microfibrils. The rate of proton spin diffusion between lignin and cellulose was consistent with the presence of microfibril arrays with approximately these dimensions and with lignin located outside them, in both earlywood and latewood. Proton spin-diffusion data for hemicelluloses were complicated by difficulties in assigning signals to glucomannans and xylans, but there was evidence for the spatial association of one group of hemicelluloses, including acetylated glucomannans, with cellulose surfaces, while another group of hemicelluloses was in spatial proximity to lignin. These data are consistent with a number of nanoscale models for the Sitka spruce cell wall, including a model in which glucomannans are associated with microfibril surfaces within the aggregate and water can penetrate partially between these surfaces, and one in which all non-cellulosic polymers and water are excluded from the interior of each microfibril aggregate.
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Ncib, Sana, Afef Barhoumi, Wided Bouguerra, Christian Larchet, Lasâad Dammak, Béchir Hamrouni, and Elimem Elaloui. "Preparation and characterization of cellulose triacetate polymer inclusion membrane blended with acetylated kraft lignin: effect of AKL." DESALINATION AND WATER TREATMENT 104 (2018): 263–72. http://dx.doi.org/10.5004/dwt.2018.21924.

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49

Ye, Dezhan, Jinfeng Kong, Shaojin Gu, Yingshan Zhou, Caoxing Huang, Weilin Xu, and Xi Zhang. "Selective aminolysis of acetylated lignin: Toward simultaneously improving thermal-oxidative stability and maintaining mechanical properties of polypropylene." International Journal of Biological Macromolecules 108 (March 2018): 775–81. http://dx.doi.org/10.1016/j.ijbiomac.2017.10.168.

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Diógenes, Otilio B. F., Davi R. de Oliveira, Lucas R. R. da Silva, Ítalo Gomes Pereira, Selma Elaine Mazzetto, Walney S. Araujo, and Diego Lomonaco. "Development of coal tar-free coatings: Acetylated lignin as a bio-additive for anticorrosive and UV-blocking epoxy resins." Progress in Organic Coatings 161 (December 2021): 106533. http://dx.doi.org/10.1016/j.porgcoat.2021.106533.

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