The Effect of Kraft Delignification of Wood on Hemicelluloses and Lignin DMSO - Accessibility

Eremeeva, T.; Klevinska, V.; Treimanis, A.

doi:10.1515/hfsg.1998.52.5.475

Cited by 2 publications

(3 citation statements)

References 4 publications

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“…Hemicelluloses influence the properties of paper made from wood fibers significantly. , The abundance and distribution of these polymers in the fiber wall as well as their chemical constitutions and molecular sizes explain, to a certain extent, the often quite large variations in the properties of paper made from fibers obtained by different processes. ,− The solution properties, adsorption behavior, and polymer strengths of the hemicelluloses are influenced to various degrees by their carbohydrate compositions and molar mass parameters (e.g., the degree of polymerization). − …”

Section: Introductionmentioning

confidence: 99%

“…16,[22][23][24] The solution properties, adsorption behavior, and polymer strengths of the hemicelluloses are influenced to various degrees by their carbohydrate compositions and molar mass parameters (e.g., the degree of polymerization). [24][25][26][27] A variety of different analytical approaches have been employed previously to determine the molar mass (MM) or the degree of polymerization (DP) of wood hemicelluloses 26,[28][29][30][31][32] Different procedures result in different types of MM or DP values. The number-average molar mass (M n ) is measured by osmometry 26,29,30 or can be calculated from the ratio between the number of reducing end groups and the total number of sugar residues present in the hemicellulose.…”

Section: Introductionmentioning

confidence: 99%

“…45,52,60,61 Although the major hemicellulose components of common pulpwoods have been characterized previously by several investigators, 1,2,28 only a few investigations on hemicelluloses derived from modern pulping processes have been described. 19,27 Therefore, the aim of the present study was to investigate the molecular properties of hemicelluloses present in pulps originating from modern cooking and totally chlorine-free (TCF) bleaching processes as well as to compare these properties with those of the corresponding hemicelluloses obtained from wood. The isolation, carbohydrate compositions, and molar mass parameters (as characterized by SEC/MALDI-MS) of hemicelluloses extracted from different species of soft-and hardwood and from different types of chemical pulps are reported here.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of the Molar Masses of Hemicelluloses from Wood and Pulps Employing Size Exclusion Chromatography and Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry

Jacobs¹,

Dahlman²

2001

Biomacromolecules

107

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The molar mass parameters for arabino-4-O-methylglucuronoxylans, arabinohexenuronoxylans, 4-O-methylglucuronoxylans, hexenuronoxylans, and galactoglucomannans extracted from wood and pulps have been determined. To characterize different types of hemicelluloses, delignified wood (spruce, pine, larch, aspen, and birch) and chemical pulps (unbleached and totally chlorine-free bleached) were extracted with dimethyl sulfoxide (DMSO) or alkaline aqueous solutions. Size exclusion chromatography (SEC) with off-line matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-MS) were employed to characterize the molar masses. The hemicellulose extracts were separated by SEC into fractions each containing components with a narrow range of molar masses and the average molar mass of each fraction subsequently determined by MALDI-MS. The molar mass parameters for the hemicelluloses were then calculated on the basis of the SEC distribution curves and MALDI-MS spectra. As expected, in most cases the hemicelluloses extracted from wood (holocellulose) exhibited higher molar masses than did the corresponding hemicelluloses from chemical pulps. The molar mass parameters for hemicelluloses isolated from pulps derived from cooking samples of the same batch of softwood chips decreased in the following order: ASAM pulp > MSSAQ pulp > kraft pulp. The lowest molar masses were demonstrated by the glucuronoxylans extracted from pulps obtained by cooking with acidic sulfite. The xylans from bleached kraft pulp were characterized by molar masses that were only slightly lower than those of the corresponding xylans from unbleached pulp. The xylans extracted into DMSO exhibited somewhat lower molar masses than did the corresponding xylans extracted into alkaline aqueous solutions. In all cases the range of molar masses demonstrated by the hemicelluloses investigated was found to be rather narrow, i.e., the polydispersity index Mw/Mn was found to be approximately 1.1-1.4.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Characterization of the Molar Masses of Hemicelluloses from Wood and Pulps Employing Size Exclusion Chromatography and Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry

Jacobs¹,

Dahlman²

2001

Biomacromolecules

107

View full text Add to dashboard Cite

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Molar mass determination of lignins by size-exclusion chromatography: towards standardisation of the method

Baumberger¹,

Abaecherli²,

Fasching³

et al. 2007

Holzforschung

203

175

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The reactivity and physicochemical properties of lignins are partly governed by their molar mass distribution. The development of reliable standard methods for determination of the molar mass distribution is not only relevant for designing technical lignins for specific applications, but also for monitoring and elucidating delignification and pulping processes. Size-exclusion chromatography (SEC) offers many advantages, such as wide availability, short analysis time, low sample demand, and determination of molar mass distribution over a wide range. A collaborative study has been undertaken within the “Eurolignin” European thematic network to standardise SEC analysis of technical lignins. The high-molar-mass fraction of polydisperse lignins was shown to be the main source of intra- and interlaboratory variations, depending on the gel type, elution solvent, detection mode, and calculation strategy. The reliability of two widespread systems have been tested: one based on alkali and a hydrophilic gel (e.g., TSK Toyopearl gel) and the other based on THF as solvent and polystyrene-based gels (e.g., Styragel). A set of practical recommendations has been deduced.

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The Effect of Kraft Delignification of Wood on Hemicelluloses and Lignin DMSO - Accessibility

Cited by 2 publications

References 4 publications

Characterization of the Molar Masses of Hemicelluloses from Wood and Pulps Employing Size Exclusion Chromatography and Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry

Characterization of the Molar Masses of Hemicelluloses from Wood and Pulps Employing Size Exclusion Chromatography and Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry

Molar mass determination of lignins by size-exclusion chromatography: towards standardisation of the method

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