Thermal characterization of kraft lignin prepared from mixed hardwoods

III, Justin Alfred Pe; Mun, Ji Sun; Mun, Sung Phil

doi:10.15376/biores.18.1.926-936

Cited by 5 publications

(6 citation statements)

References 19 publications

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“…The weight loss in this region is attributed to the cleavage of interunit linkages in lignin, releasing monomeric phenols into the vapor phase [ 42 ]. Specifically, the peak at 287 °C signifies the degradation of aliphatic side chains, particularly the scission of β-O-4 ether linkages, while the peak at 370 °C indicates the degradation of methoxyl groups [ 43 ], based on information regarding gases released during pyrolysis [ 44 ]. Between 400 and 600 °C, the weight loss is primarily attributed to the decomposition or condensation of the aromatic ring [ 42 , 45 ].…”

Section: Resultsmentioning

confidence: 99%

“…The MWL was derivatized using trimethylsilylation, as described by Pe et al [ 43 ]. Py-GC/MS was then conducted at the CURF under the conditions shown in Table 13 .…”

Section: Methodsmentioning

confidence: 99%

“…In the 2nd heating cycle, the T g of MWL was determined to be 159 Furthermore, under inert conditions, the DTGmax (287 °C) was lower than that obtained under oxidative conditions (544 °C). This can be attributed to the difficulty involved in degrading oxidized condensed aromatic moieties [43].…”

Section: Dscmentioning

confidence: 99%

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Structural and Thermal Characterization of Milled Wood Lignin from Bamboo (Phyllostachys pubescens) Grown in Korea

Mun,

Mun

2023

Molecules

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The structural and thermal characterization of milled wood lignin (MWL) prepared from bamboo (Phyllostachys pubescens) grown in Korea was investigated, and the results were compared with bamboo MWLs from other studies. The C9 formula of the bamboo MWL was C9H7.76O3.23N0.02 (OCH3)1.41. The Mw and Mn of MWL were 13,000 and 4400 Da, respectively, which resulted in a polydispersity index (PDI) of 3.0. The PDI of the prepared MWL was higher than other bamboo MWLs (1.3–2.2), suggesting a broader molecular weight distribution. The structural features of MWL were elucidated using FT-IR spectroscopy and NMR techniques (1H, 13C, HSQC, 31P NMR), which indicate that MWL is of the HGS-type lignin. The major lignin linkages (β-O-4, β-β, β-5) were not different from other bamboo MWLs. The syringyl/guaiacyl ratio, determined from 1H NMR, was calculated as 0.89. 31P NMR revealed variations in hydroxyl content, with a higher aliphatic hydroxyl content in MWL compared to other bamboo MWLs. Thermal properties were investigated through TGA, DSC, and pyrolysis-GC/MS spectrometry (Py-GC/MS). The DTGmax of MWL under inert conditions was 287 °C, and the Tg of MWL was 159 °C. Py-GC/MS at 675 °C revealed a syringyl, guaiacyl, p-hydroxyphenyl composition of 17:37:47.

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Section: Resultsmentioning

confidence: 99%

“…The MWL was derivatized using trimethylsilylation, as described by Pe et al [ 43 ]. Py-GC/MS was then conducted at the CURF under the conditions shown in Table 13 .…”

Section: Methodsmentioning

confidence: 99%

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Structural and Thermal Characterization of Milled Wood Lignin from Bamboo (Phyllostachys pubescens) Grown in Korea

Mun,

Mun

2023

Molecules

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“…After kraft pulping, lignin was separated and purified from the black liquor using acid precipitation method with sulfuric acid. Detailed information on pulping conditions, purification process, as well as chemical, structural, and thermal characterization of KL can be found in previous works (Mun et al 2021(Mun et al , 2022Pe et al 2023). The thoroughly dried KL was stored at ambient temperature and was used as dye material.…”

Section: Methodsmentioning

confidence: 99%

Potential of hardwood kraft lignin as a bio-based dye for cotton fabrics

Mun,

Mun

2023

BioRes

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The dyeing characteristics of hardwood kraft lignin (KL) were investigated on cotton fabrics, assessing its potential as a sustainable and environmentally friendly dye. Dyeability was evaluated by varying the KL concentrations, temperature, and time. An aqueous solution of Na2CO3 (1.0%) as the dye bath and a fabric-to-liquor ratio of 1:50 were used. Cationizing effects were studied using (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC), and the mordanting effects of various mordants were also evaluated. Post-mordanting was performed with FeSO4, FeCl2, Fe-lactate (Fe-lac), MgSO4, CuCl2, CuSO4, and Al2(SO4)3. A mordant concentration of 1 mM o.w.f. (0.5 mM for Al2(SO4)3), with a liquor ratio of 1:30, at 60 °C for 30 min were employed. Suitable dyeing conditions were 2.0% o.w.b., 90 °C, and 90 min, resulting in a brownish color of the cotton fabric. The fabrics exhibited a range of light brown to light grayish brown colors and showed lighter colors than the untreated fabrics when mordanted with MgSO4 and Al2(SO4)3. The color difference (ΔE) between cationized and uncationized cotton fabrics was 3.48. From the colorfastness assessment, KL-dyed cotton fabric showed good rubbing and washing fastness for staining, but poor light and washing fastness for fading.

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“…A calibration curve was prepared using polystyrene in the range of 1480~1,233,000 g/mol. The thermal oxidative degradation and stability of the lignin samples were subjected to thermogravimetric analysis (TGA SDT650, TA Instruments, Milford, MA, USA) [57]. The lignin samples were placed in aluminum crucibles and tested between room temperature and 800 • C at a heating rate of 10 • C/min under nitrogen conditions.…”

Section: Characterizations Of Ligninmentioning

confidence: 99%

Switchable Deep Eutectic Solvents for Lignin Dissolution and Regeneration

Li,

Qi,

Yang

et al. 2023

Polymers

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Deep eutectic solvents (DESs) are promising for lignin dissolution and extraction. However, they usually possess high polarity and are difficult to recycle. To overcome this drawback, a variety of switchable ionic liquids (SILs) composed of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and alcohols was synthesized and screened. According to the thermodynamic modeling suggestions, the selected DBU–HexOH SIL was coupled with hydrogen-bond donors to form switchable-DES (SDES) systems with moderated viscosity, conductivity, and pH while maintaining switchability. The SDESs produced a well-improved lignin and lignin model compound solubility compared with those of SILs; charging CO2 into SDES (SDESCO2) caused a further increase in solubility. The solubility (25 °C) of syringic acid, ferulic acid, and milled wood lignin in SDESCO2 reached 230.57, 452.17, and 279.12 mg/g, respectively. Such SDES-dissolved lignin can be regenerated using acetone as an anti-solvent. The SDES-regenerated lignin exhibited a well-preserved structure with no noticeable chemical modifications. Furthermore, the SDESCO2 lignin possessed a higher molecular weight (Mw = 10,340 g/mol; Mn = 7672 g/mol), improved uniformity (polydispersity index = 1.35), and a higher guaiacyl lignin unit content compared with the original milled wood lignin. The SDES system proposed in the present work could benefit the fractionation of lignin compounds and facilitate downstream industrial processes.

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Thermal characterization of kraft lignin prepared from mixed hardwoods

Cited by 5 publications

References 19 publications

Structural and Thermal Characterization of Milled Wood Lignin from Bamboo (Phyllostachys pubescens) Grown in Korea

Structural and Thermal Characterization of Milled Wood Lignin from Bamboo (Phyllostachys pubescens) Grown in Korea

Potential of hardwood kraft lignin as a bio-based dye for cotton fabrics

Switchable Deep Eutectic Solvents for Lignin Dissolution and Regeneration

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