Chemistry and Structure of Lignin

Akpan, E. I.

doi:10.1007/978-3-030-18792-7_1

Cited by 5 publications

(12 citation statements)

References 194 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This has important consequences in the 3-D structure of the resulting heteropolymers, because S units cannot participate in interunit linkages involving their 5-positions, which are occupied by methoxy substituents and indeed unavailable for participation in other bonds. 29 Consequently, S units cannot participate in 5−5, 4-O−5, and β−5 linkages. As a result, decidedly more cross-links are present in softwood lignin (nearly no S units) in comparison with hardwood lignin and, to a certain extent, in grass lignin (about 25% S units, although with high variations among different botanical species).…”

Section: ■ An Overview On Lignin General Features and Structurementioning

confidence: 99%

“…Therefore, although present in substantially lower amounts, grass lignin forms a denser network with respect to the much more abundant hardwood lignin and is conceivably harder to remove. 29 ■ GRASS LIGNIN: RECALCITRANT THOUGH SCARCE For the reasons underlined above, grasses (both crops and wastes coming from herbaceous crop processing) are of high interest as inexpensive and rich sources of polysaccharides and therefore fermentable sugars, as well as other sugar-derived chemicals. However, such potential is hindered by the recalcitrance of their lignin fraction, 30 which must be removed in whole or at least in part to fully exploit the polysaccharides.…”

Section: ■ An Overview On Lignin General Features and Structurementioning

confidence: 99%

“…As noted above, lignins of different botanical origin differ considerably in the proportions among the three main monolignols. This has important consequences in the 3-D structure of the resulting heteropolymers, because S units cannot participate in interunit linkages involving their 5-positions, which are occupied by methoxy substituents and indeed unavailable for participation in other bonds . Consequently, S units cannot participate in 5–5, 4-O–5, and β–5 linkages.…”

Section: An Overview On Lignin General Features and Structurementioning

confidence: 99%

“…As a result, decidedly more cross-links are present in softwood lignin (nearly no S units) in comparison with hardwood lignin and, to a certain extent, in grass lignin (about 25% S units, although with high variations among different botanical species). Therefore, although present in substantially lower amounts, grass lignin forms a denser network with respect to the much more abundant hardwood lignin and is conceivably harder to remove …”

Section: An Overview On Lignin General Features and Structurementioning

confidence: 99%

See 3 more Smart Citations

Recent Developments in the Delignification and Exploitation of Grass Lignocellulosic Biomass

Tocco

Carucci

Monduzzi

et al. 2021

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

Biofuels could be defined as the fuels of the future, although much work is still required before they will replace fossil fuels. In this review, lignocellulosic biomass based on straw and related crops and wastes is described concerning its lignin contents, structure, and properties, and an overview on the means of current and predictable delignification protocols is presented. The discussion is focused on herbaceous monocot materials and their available pretreatments (physical, chemical, and enzymatic), with special emphasis on fungal ligninolytic enzymes and the most recent findings and developments in their current application, issues, and perspectives.

show abstract

Section: ■ An Overview On Lignin General Features and Structurementioning

confidence: 99%

Section: ■ An Overview On Lignin General Features and Structurementioning

confidence: 99%

Section: An Overview On Lignin General Features and Structurementioning

confidence: 99%

Section: An Overview On Lignin General Features and Structurementioning

confidence: 99%

See 2 more Smart Citations

Recent Developments in the Delignification and Exploitation of Grass Lignocellulosic Biomass

Tocco

Carucci

Monduzzi

et al. 2021

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

show abstract

“…42 During thermostabilization, thermosetting properties are only achieved by providing sufficient oxygen for changing the structure of lignin by bond cleavage and oxidation including dehydration, cyclization, and cross-linking. 35,43,44 In some cases, the thermostabilization process required from ∼7 h to more than 3 days depending on the types of lignin and fiber compositions to achieve infusible fibers. 31,45−47 Therefore, various alternative approaches have been studied to improve the stabilization of lignin fibers.…”

Section: ■ Introductionmentioning

confidence: 99%

Stable Lignin-Rich Nanofibers for Binder-Free Carbon Electrodes in Supercapacitors

Khamnantha

Homla-or

Suttisintong

et al. 2021

ACS Appl. Nano Mater.

View full text Add to dashboard Cite

In this work, 1,2,4,5-benzenetetracarboxylic acid (BT) is used as a cross-linker to improve the oxidative thermostabilization of lignin-rich nanofibers so that the activated carbon nanofiber (ACNF) sheets can be prepared from lignins. As sources, we used organosolv lignins from sugarcane bagasse (LB), para rubber wood chip (LR), and palm kernel shell (LP). The addition of BT imparts hydrogen bond interactions between BT and lignin and increases the oxidation degree of lignin during the stabilization, enabling retention of nanofiber morphology after heat treatments. The preparation of activated carbon in the form of nanofibers substantially enhances the specific surface area of the materials when compared with the activated carbon powders from pure lignins. The properties of the resulting ACNFs are influenced by the structure and composition of lignins. With the synergistic effects of a small fiber diameter (688 ± 80 nm), a high content of heteroatom (O atomic content ∼5.1%), a high graphitic carbon structure (I D /I G ratio ∼0.98), a high conductivity (N I>0.1nA /A ∼3479 ± 404 pixel μm −2 at 0.5 V), and a high specific surface area (∼2195 m 2 g −1 ), the ACNFs from LB show the highest specific capacitance of 182 F g −1 (at a current density of 0.1 A g −1 in 1.0 M H 2 SO 4 electrolyte) with good cycling stability (95.7% capacitance retention after 6000 cycles). A maximum energy density of 31 W h kg −1 at a power density of 240 W kg −1 can be achieved from the LB/PEO/BT ACNFs. Their performance is almost comparable to that of polyacrylonitrile ACNFs. These findings demonstrate a simple and effective approach to produce lignin-based ACNFs from diverse biomass feedstock for sustainable development of renewable materials for supercapacitor electrodes.

show abstract

Solvent‐free grafting route to develop thin and flexible polymer film from lignin

Saikia,

Dutta,

Singh

2024

Polymers for Advanced Techs

View full text Add to dashboard Cite

The recent advancements on the development of sustainable copolymers from lignin, has led us to explore a novel two‐step methodology for the development of lignin‐derived copolymers for flexible film preparation. In this work, firstly, chemical modification of lignin with itaconic acid (IA) in green solvent followed by grafting with lactic acid (LA) via solvent free polycondensation pathway was used to produce Lig‐g‐PLA copolymers. The effect of various reaction parameters like IA and LA amount, reaction time, solvent, temperature was studied to optimize yield of the reaction. Analytical techniques (FT‐IR, NMR, and XPS) confirmed successful chemical modification of lignin and copolymer (Lig‐g‐PLA) synthesis. The change in flexibility behavior of the polymer thin films (250 microns) prepared through hydraulic hot press method found to be dependent on the LA grafting. Notably, smooth surface of the films prepared with LA amount (IAL:LA 1:3 wt ratio) indicates enhanced compatibility between copolymer molecules due to the grafting of LA. Additionally, films prepared with a higher LA amount (i.e., IAL:LA 1:4 wt ratio) exhibited superior mechanical property with 3 times higher storage modulus as compared to the film prepared with lower LA amount (i.e., IAL:LA 1:2 wt ratio).

show abstract

Chemistry and Structure of Lignin

Cited by 5 publications

References 194 publications

Recent Developments in the Delignification and Exploitation of Grass Lignocellulosic Biomass

Recent Developments in the Delignification and Exploitation of Grass Lignocellulosic Biomass

Stable Lignin-Rich Nanofibers for Binder-Free Carbon Electrodes in Supercapacitors

Solvent‐free grafting route to develop thin and flexible polymer film from lignin

Contact Info

Product

Resources

About