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Pedram Fatehi - One of the best experts on this subject based on the ideXlab platform.
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Phosphorylated Kraft Lignin with improved thermal stability.
International journal of biological macromolecules, 2020Co-Authors: Cong Gao, Long Zhou, Shuangquan Yao, Chengrong Qin, Pedram FatehiAbstract:Abstract The low cost, environmental friendliness, and reproducibility of Kraft Lignin (KL) make it a potential candidate for the development of new green material. The phosphorylation of KL can extend its application as a flame-retardant material. Herein, the phosphorylated Kraft Lignin (PKL) was systematically fabricated in a sustainable process by utilizing a green phosphating reagent, NH4H2PO4, in the presence of urea. The influence of the reaction parameters, i.e., reaction time and temperature, and NH4H2PO4/Lignin ratio on the phosphorylation process were investigated. Advanced characterization techniques including 1H NMR, 31P NMR, and XPS confirmed that the phosphorus groups were successfully introduced to Lignin molecules. The active phenolic and aliphatic hydroxy groups of Kraft Lignin underwent a nucleophilic substitution reaction with the phosphate group to generate phosphorylated Lignin. Compared with KL, PKL showed excellent thermal stability, and its maximum decomposition temperature was 620 °C compared with 541 °C for KL.
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Modification of Kraft Lignin with Dodecyl Glycidyl Ether.
ChemistryOpen, 2019Co-Authors: Norah Alwadani, Pedram FatehiAbstract:Kraft Lignin (KL) is extensively produced in industry but is mainly burned as fuel. To broaden its use, KL was grafted with dodecyl glycidyl ether to alter its thermal properties. The reaction of KL with dodecyl glycidyl ether (DGE) was analyzed using nuclear magnetic resonance (NMR), Fourier infrared spectroscopy (FT-IR) and elemental analysis. Alternatively, KL was methylated to mask its phenolic hydroxy groups to investigate how phenolic hydroxy groups impact the grafting of the alkyl chain of DGE onto Lignin (methylated Kraft Lignin, MKL). The methylation facilitated the molecular weight enhancement and thermal stability reduction of Kraft Lignin via grafting with DGE. The influence of grafting alkyl chains on the structural and thermal properties of KL and MKL was studied using thermogravimetric analysis and differential scanning calorimetry analysis. Our data suggest that, due to their high molecular weights and lower glass transition temperatures, the produced Lignin derivatives may be promising feedstocks for composite production.
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Sulfonation of Phenolated Kraft Lignin to Produce Water Soluble Products
Journal of Wood Chemistry and Technology, 2019Co-Authors: Weijue Gao, John P. W. Inwood, Pedram FatehiAbstract:Kraft Lignin is water insoluble and has limited end-use applications. To produce water soluble Lignin-based products, the modification of softwood Kraft Lignin through phenolation followed by sulfo...
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Production of Sulfur Containing Kraft Lignin Products
BioResources, 2017Co-Authors: John P. W. Inwood, Leila Pakzad, Pedram FatehiAbstract:Kraft Lignin is produced in great quantities in many countries, but is mainly used as an energy source. To valorize its potential end-use applications, softwood Kraft Lignin was modified via sulfuric acid and sodium sulfite treatments in this study. The modification of Kraft Lignin through a sulfuric acid treatment resulted in a modified Lignin (SA-Lignin) with a charge density of 0.8 meq/g but with a limited water solubility. The sulfonation of the Kraft Lignin through a sodium sulfite treatment induced a soluble sulfonated Lignin (SS-Lignin) with a charge density of 1.4 meq/g, which was obtained under the conditions of 90 °C, 4 h, and 0.67 Na2SO3/Lignin molar ratio. The elemental compositions, molecular weights, and thermal and rheological properties of modified Lignin samples were characterized.
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Production of Water-Soluble Hardwood Kraft Lignin via Sulfomethylation Using Formaldehyde and Sodium Sulfite
ACS Sustainable Chemistry & Engineering, 2015Co-Authors: Mohan K.r. Konduri, Pedram FatehiAbstract:Kraft Lignin can be extracted from black liquor (i.e., spent liquor) of a Kraft pulping process to produce value-added chemicals, but its limited water solubility hampers its end-use applications. The main objective of this study was to investigate the sulfomethylation of Kraft Lignin to produce water-soluble Kraft Lignin with an anionic charge density. In this work, hardwood Kraft Lignin was modified with formaldehyde and sodium sulfite under alkali conditions. The optimum conditions for sulfomethylation were 0.5 M NaOH(aq), 0.9 mol/mol sodium hydroxymethyl sulfonate/Lignin at 100 °C for 3 h, and 20 g/L Lignin concentration. The resulting Lignin had a charge density of −1.60 mequiv/g and sulfonate group content of 1.48 mmol/g. The molecular weight, structure, thermal behavior, and elemental analyses of the product were also assessed. The modified Lignin was used as a cement dispersant, and the dispersibility of cement was increased from 60 to 155 mm by adding 1.2 wt % of sulfomethylated Lignin to cement....
Dimitris S. Argyropoulos - One of the best experts on this subject based on the ideXlab platform.
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On the structure of softwood Kraft Lignin
Green Chemistry, 2017Co-Authors: Claudia Crestini, Heiko Lange, Marco Sette, Dimitris S. ArgyropoulosAbstract:Two constitutional structural schemes are proposed attempting to unify and rationalize a series of focused NMR and chromatographic determinations aimed at providing an integrated picture for the structure of softwood Kraft Lignin. The complexity of native softwood Lignin when coupled with the complexity of the Kraft pulping process is known to lead to a rather heterogeneous material that has eluted us to date. The present work embarks at applying state-of-the-art quantitative 1D and 2D NMR methods on carefully isolated softwood Kraft Lignin samples and fractions. The accumulated data, when coupled with size exclusion chromatography, mass spectrometric analyses and literature accounts that pertain to the chemistry of Kraft pulping, provide the following picture for softwood Kraft Lignin. Softwood Kraft Lignin is composed of two distinct fractions that can be separated by using anhydrous acetone. The acetone insoluble fraction is a somewhat branched polymeric material that still contains a variety of native wood Lignin bonding patterns, albeit in significantly reduced abundance, as well as new structures induced during the process. The acetone soluble fraction is a significantly more branched and less polymeric material with an abundance of chemical structures that may be created when oligomeric phenols react under Kraft pulping conditions. To account for the presence of the various moieties in these two fractions, Kraft pulping fragmentation and repolymerization chemistries are extensively invoked, including radical processes initiated by sulfur.
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Effect of Fatty Acid Esterification on the Thermal Properties of Softwood Kraft Lignin
ACS Sustainable Chemistry & Engineering, 2016Co-Authors: Klaus A. Y. Koivu, Dimitris S. Argyropoulos, Hasan Sadeghifar, Paula Annukka Nousiainen, Jussi SipiläAbstract:Esterification of Kraft Lignin inherently addresses its potential for thermoplastic applications either on its own or as a component of polymer blends. In this effort, we have investigated the selectivity of softwood Kraft Lignin toward esterification via acylation. LignoBoost Kraft Lignin was esterified with acetyl (C2), octanoyl (C8), lauroyl (C12), and palmitoyl (C16) chlorides at various molar ratios with respect to the total hydroxyls present. Quantitative 31P NMR spectroscopy, Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC) were used to evaluate the selectivity and efficiency of these reactions on the various hydroxyl groups present. The C8–C16 acyl chlorides showed distinct enhanced reactivity toward the aliphatic hydroxyl groups, whereas C2 acyl chloride was found to react uniformly with any available OH irrespective of their chemical nature. The effects of long chain acylation on the polymer and material properties were also examined using solution viscosit...
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Kraft Lignin chain extension chemistry via propargylation oxidative coupling and claisen rearrangement
Biomacromolecules, 2013Co-Authors: Sanghamitra Sen, Hasan Sadeghifar, Dimitris S. ArgyropoulosAbstract:Despite its aromatic and polymeric nature, the heterogeneous, stochastic, and reactive characteristics of softwood Kraft Lignin seriously limit its potential for thermoplastic applications. Our continuing efforts toward creating thermoplastic Lignin polymers are now focused at exploring propargylation derivatization chemistry and its potential as a versatile novel route for the eventual utilization of technical Lignins with a significant amount of molecular control. To do this, we initially report the systematic propargylation of softwood Kraft Lignin. The synthesized derivatives were extensively characterized with thermal methods (DSC, TGA), (1)H, (13)C, and quantitative (31)P NMR and IR spectroscopies. Further on, we explore the versatile nature of the Lignin pendant propargyl groups by demonstrating two distinct chain extension chemistries; the solution-based, copper-mediated, oxidative coupling and the thermally induced, solid-state, Claissen rearrangement polymerization chemistries. Overall, we show that it is possible to modulate the reactivity of softwood Kraft Lignin via a combination of methylation and chain extension providing a rational means for the creation of higher molecular weight polymers with the potential for thermoplastic materials and carbon fibers with the desired control of structure-property relations.
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toward thermoplastic Lignin polymers part ii thermal polymer characteristics of Kraft Lignin derivatives
Bioresources, 2013Co-Authors: Hasan Sadeghifar, Dimitris S. ArgyropoulosAbstract:This work focused on providing a molecular understanding of the way the polymeric properties of Kraft Lignin and its derivatives are affected by various thermal treatments. This information was then correlated with the polymeric properties of the materials (glass transition temperature (Tg), molecular weight characteristics, and thermal stability) for a series of selectively and progressively derivatized softwood Kraft Lignin samples. Softwood Kraft Lignin was highly susceptible to thermally induced reactions that caused its molecular characteristics to be severely altered with the concomitant formation of irreversible cross-linking. However, by fully methylating the phenolic OH groups from within the structure of softwood Kraft Lignin, the thermal stability of these materials was dramatically enhanced and their Tg reduced. While optimum thermal stability and melt re-cycling was observed with the fully methylated derivatives, fully oxypropylated phenolic substitution did not offer the same possibilities. The accumulated data is aimed at providing the foundations for a rational design of single component, Lignin-based thermoplastic materials with reproducible polymeric properties when thermally processed in a number of manufacturing cycles.
Göran Gellerstedt - One of the best experts on this subject based on the ideXlab platform.
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Softwood Kraft Lignin: Raw material for the future
Industrial Crops and Products, 2015Co-Authors: Göran GellerstedtAbstract:Large quantities of Kraft Lignin are formed in the pulp industry. Although the vast majority is used for internal energy production at mill sites, modern pulping technology allows for a partial outtake of Lignin without disturbance of the energy balance in the mill. At present, Lignin from softwood pulping is available in commercial quantities and it can be assumed that this amount will rapidly increase in the future. Therefore, development of material systems based on softwood Kraft Lignin should be beneficial for the future sustainable society and add value to a renewable resource. In this review, the formation, structure, and properties of softwood Kraft Lignin is summarized and it is suggested that, depending on final use, an optimization of Lignin properties is done through selected fractionation and purification.
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Oxidative stabilisation of Kraft Lignin for carbon fibre production
Holzforschung, 2012Co-Authors: Ida Brodin, Göran Gellerstedt, Marie Ernstsson, Elisabeth SjoholmAbstract:With the aim of investigating Kraft Lignin as a raw material for carbon fibre production, different Lignins have been stabilised in air at conditions varied according to a full factorial experiment ...
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The behavior of Kraft Lignin during thermal treatment
Journal of Analytical and Applied Pyrolysis, 2010Co-Authors: Ida Brodin, Elisabeth Sjoholm, Göran GellerstedtAbstract:Purified Kraft Lignin fractions from technical pulping liquors of softwood and hardwood have been subjected to step-wise analytical pyrolysis in the temperature interval 200-900 degrees C. The hete ...
Hasan Sadeghifar - One of the best experts on this subject based on the ideXlab platform.
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Effect of Fatty Acid Esterification on the Thermal Properties of Softwood Kraft Lignin
ACS Sustainable Chemistry & Engineering, 2016Co-Authors: Klaus A. Y. Koivu, Dimitris S. Argyropoulos, Hasan Sadeghifar, Paula Annukka Nousiainen, Jussi SipiläAbstract:Esterification of Kraft Lignin inherently addresses its potential for thermoplastic applications either on its own or as a component of polymer blends. In this effort, we have investigated the selectivity of softwood Kraft Lignin toward esterification via acylation. LignoBoost Kraft Lignin was esterified with acetyl (C2), octanoyl (C8), lauroyl (C12), and palmitoyl (C16) chlorides at various molar ratios with respect to the total hydroxyls present. Quantitative 31P NMR spectroscopy, Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC) were used to evaluate the selectivity and efficiency of these reactions on the various hydroxyl groups present. The C8–C16 acyl chlorides showed distinct enhanced reactivity toward the aliphatic hydroxyl groups, whereas C2 acyl chloride was found to react uniformly with any available OH irrespective of their chemical nature. The effects of long chain acylation on the polymer and material properties were also examined using solution viscosit...
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Kraft Lignin chain extension chemistry via propargylation oxidative coupling and claisen rearrangement
Biomacromolecules, 2013Co-Authors: Sanghamitra Sen, Hasan Sadeghifar, Dimitris S. ArgyropoulosAbstract:Despite its aromatic and polymeric nature, the heterogeneous, stochastic, and reactive characteristics of softwood Kraft Lignin seriously limit its potential for thermoplastic applications. Our continuing efforts toward creating thermoplastic Lignin polymers are now focused at exploring propargylation derivatization chemistry and its potential as a versatile novel route for the eventual utilization of technical Lignins with a significant amount of molecular control. To do this, we initially report the systematic propargylation of softwood Kraft Lignin. The synthesized derivatives were extensively characterized with thermal methods (DSC, TGA), (1)H, (13)C, and quantitative (31)P NMR and IR spectroscopies. Further on, we explore the versatile nature of the Lignin pendant propargyl groups by demonstrating two distinct chain extension chemistries; the solution-based, copper-mediated, oxidative coupling and the thermally induced, solid-state, Claissen rearrangement polymerization chemistries. Overall, we show that it is possible to modulate the reactivity of softwood Kraft Lignin via a combination of methylation and chain extension providing a rational means for the creation of higher molecular weight polymers with the potential for thermoplastic materials and carbon fibers with the desired control of structure-property relations.
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toward thermoplastic Lignin polymers part ii thermal polymer characteristics of Kraft Lignin derivatives
Bioresources, 2013Co-Authors: Hasan Sadeghifar, Dimitris S. ArgyropoulosAbstract:This work focused on providing a molecular understanding of the way the polymeric properties of Kraft Lignin and its derivatives are affected by various thermal treatments. This information was then correlated with the polymeric properties of the materials (glass transition temperature (Tg), molecular weight characteristics, and thermal stability) for a series of selectively and progressively derivatized softwood Kraft Lignin samples. Softwood Kraft Lignin was highly susceptible to thermally induced reactions that caused its molecular characteristics to be severely altered with the concomitant formation of irreversible cross-linking. However, by fully methylating the phenolic OH groups from within the structure of softwood Kraft Lignin, the thermal stability of these materials was dramatically enhanced and their Tg reduced. While optimum thermal stability and melt re-cycling was observed with the fully methylated derivatives, fully oxypropylated phenolic substitution did not offer the same possibilities. The accumulated data is aimed at providing the foundations for a rational design of single component, Lignin-based thermoplastic materials with reproducible polymeric properties when thermally processed in a number of manufacturing cycles.
Claudia Crestini - One of the best experts on this subject based on the ideXlab platform.
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On the structure of softwood Kraft Lignin
Green Chemistry, 2017Co-Authors: Claudia Crestini, Heiko Lange, Marco Sette, Dimitris S. ArgyropoulosAbstract:Two constitutional structural schemes are proposed attempting to unify and rationalize a series of focused NMR and chromatographic determinations aimed at providing an integrated picture for the structure of softwood Kraft Lignin. The complexity of native softwood Lignin when coupled with the complexity of the Kraft pulping process is known to lead to a rather heterogeneous material that has eluted us to date. The present work embarks at applying state-of-the-art quantitative 1D and 2D NMR methods on carefully isolated softwood Kraft Lignin samples and fractions. The accumulated data, when coupled with size exclusion chromatography, mass spectrometric analyses and literature accounts that pertain to the chemistry of Kraft pulping, provide the following picture for softwood Kraft Lignin. Softwood Kraft Lignin is composed of two distinct fractions that can be separated by using anhydrous acetone. The acetone insoluble fraction is a somewhat branched polymeric material that still contains a variety of native wood Lignin bonding patterns, albeit in significantly reduced abundance, as well as new structures induced during the process. The acetone soluble fraction is a significantly more branched and less polymeric material with an abundance of chemical structures that may be created when oligomeric phenols react under Kraft pulping conditions. To account for the presence of the various moieties in these two fractions, Kraft pulping fragmentation and repolymerization chemistries are extensively invoked, including radical processes initiated by sulfur.
