Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Extended Mercerization Prior to Carboxymethyl Cellulose Preparation
Karlstad University, Faculty of Technology and Science, Avdelningen för kemiteknik.
2010 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Carboxymethyl cellulose (CMC) is produced commercially in a two-stage process consisting of a mercerization stage, where the pulp is treated with alkali in a water alcohol solution, followed by an etherification stage in which monochloroacetic acid is added to the pulp slurry. In this thesis an extended mercerization stage of a spruce ether pulp was investigated where the parameters studied were the ratio of cellulose I and II, concentration of alkali, temperature and retention time. The influence of the mercerization stage conditions on the etherification stage, were evaluated as the degree of substitution (DS) of the resulting CMC and the filterability of CMC dissolved in water at a concentration of 1%. The DS results suggested that the NaOH concentration in the mercerization stage was the most important of the parameters studied. When the NaOH concentration in the mercerization step was low (9%), a high cellulose II content in the pulp used was found to have no negative impact on the DS of the resulting CMC compared with pulps with only cellulose I. However, when the NaOH concentration was high (27.5%), pulps with high content of cellulose II showed a lower reactivity than those with only cellulose I with respect to the DS of the CMC obtained after a given charge of NaMCA.

The results obtained from the filtration ability study of CMC water solutions suggested that both the amount of cellulose II in the original pulp and the temperature had a negative influence on the filtration ability whereas the NaOH concentration in the mercerization stage had a positive influence. The filtration ability was assumed to be influenced highly by the presence of poorly reacted cellulose segments. A retention time between 1-48 h in the mercerization stage had no effect on either the DS or the filtration ability of the CMC.

Using NIR FT Raman spectroscopy molecular structures of CMC and its gel fraction were analyzed with respect to the conditions used in the extended mercerization stage. Here it was found that the alkaline concentration had a very strong influence on the following etherification reaction. FT Raman spectra of CMC samples and their gel fractions prepared with low NaOH concentrations (9%) in the mercerization stage indicated an incomplete transformation of cellulose to Na-cellulose before carboxymethylation to CMC. Low average DS values of the CMC, i.e. between 0.42 and 0.50, were yielded. Such CMC dissolved in water caused very thick and semi solid gum-like gels, probably due to an uneven distribution of substituting groups along the cellulose backbone. FT Raman spectra of CMC mercerized with alkaline concentrations at 18.25 and 27.5% in the mercerization stage indicated, however, that all of the cellulose molecules were totally transferred to CMC of high DS, i.e. between 0.88 and 1.05. When dissolved in water such CMC caused gels when they were prepared from ether pulp with a high fraction of cellulose II.

Place, publisher, year, edition, pages
Karlstad: Karlstad University , 2010. , p. 51
Series
Karlstad University Studies, ISSN 1403-8099 ; 2010:22
Keywords [en]
Carboxymethyl cellulose, Mercerization, DS, FT Raman spectroscopy, Filtration ability
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
URN: urn:nbn:se:kau:diva-5947ISBN: 978-91-7063-314-0 (print)OAI: oai:DiVA.org:kau-5947DiVA, id: diva2:326030
Presentation
2010-10-01, 9C 204 (Rejmersalen), Karlstads universitet, KARLSTAD, 13:15 (Swedish)
Opponent
Supervisors
Available from: 2010-10-11 Created: 2010-06-21 Last updated: 2011-10-04Bibliographically approved
List of papers
1. Quantitative analysis of the transformation process of cellulose I → cellulose II using NIR FT Raman spectroscopy and chemometric methods
Open this publication in new window or tab >>Quantitative analysis of the transformation process of cellulose I → cellulose II using NIR FT Raman spectroscopy and chemometric methods
2009 (English)In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 16, p. 407-415Article in journal (Refereed) Published
Abstract [en]

This paper reports a new, successful, utilization of NIR FT Raman spectroscopy for determinining the polymorphic transformation of native cellulose I into the allomorph cellulose II quantitatively. A rapid prediction of the transformation order is made possible by applying multivariate linear regression to the FT Raman spectral data of alkali-treated cellulose pulps. Simultaneously, changes in the crystallinity of cellulose I of these pulps were followed with respect to the lattice conversion process. The application of both multivariate quantification methods to the FT Raman spectra of the alkali-treated pulps yields a corrected polymorphic transformation order and enables the quantitative description to be made of the cellulose lattice conversion process as a system consisting of three participating forms of cellulose: crystalline cellulose I, amorphous cellulose and cellulose II.

National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-6418 (URN)10.1007/s10570-009-9286-0 (DOI)
Available from: 2010-09-28 Created: 2010-09-28 Last updated: 2017-12-12Bibliographically approved
2. The influence of extended mercerization on some properties of carboxymethyl cellulose (CMC)
Open this publication in new window or tab >>The influence of extended mercerization on some properties of carboxymethyl cellulose (CMC)
2012 (English)In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 66, p. 21-27Article in journal (Refereed) Published
Abstract [en]

Carboxymethyl cellulose (CMC) is produced commercially in a two stage process consisting of a mercerization stage in which the pulp is treated with alkali in a water alcohol solution and a second etherification stage whereby monochloro-acetic acid is added to the pulp slurry. In this study, the influence of the conditions of an extended mercerization stage was evaluated on the etherification stage concerning the degree of substitution (DS) and the filterability of the resulting CMC. The parameters studied were: (1) the ratio of cellulose I and cellulose II in the original pulp, (2) the concentration of alkali, (3) the temperature and (4) the retention time in the mercerization stage. The DS results indicate that the NaOH concentration in the mercerization stage is the most important among the parameters studied. When the NaOH concentration in the mercerization stage was high (27.5%), cellulose II showed a lower reactivity than cellulose I with respect to the DS obtained in the resulting CMC. The results from the filtration ability of CMC water solutions are interpreted that the amount of cellulose II in the original pulp and the temperature has a negative influence, while the NaOH concentration in the mercerization stage has a positive influence on the filtration ability. Retention time between 1 h–48 h in the mercerization stage had no effect on the DS or the filtration value. The filtration ability was assumed to be highly influenced by the presence of poorly reacted cellulose segments. The CMC samples with the lowest filtration ability at a given DS can be assumed to have the highest degree of unevenly substituted segments.

Keywords
alkali, carboxymethyl cellulose, cellulose I, cellulose II, degree of substitution, filterability, mercerization
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-6419 (URN)10.1515/HF.2011.131 (DOI)000298290400003 ()
Available from: 2010-09-28 Created: 2010-09-28 Last updated: 2017-12-12Bibliographically approved
3. Carboxymethyl cellulose produced at different mercerization conditions and characterized by NIR FT Raman spectroscopy and chemometric methods
Open this publication in new window or tab >>Carboxymethyl cellulose produced at different mercerization conditions and characterized by NIR FT Raman spectroscopy and chemometric methods
2013 (English)In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 8, no 2, p. 1918-1932Article in journal (Refereed) Published
Keywords
carboxymethyl cellulose, cellulose backbone structure, degree of substitution, extended mercerization, gel formation, multivariate analytical methods, NIR FT Taman spectroscopy
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-6420 (URN)000315386400037 ()
Available from: 2010-09-28 Created: 2010-09-28 Last updated: 2017-12-12Bibliographically approved

Open Access in DiVA

fulltext(1167 kB)2378 downloads
File information
File name FULLTEXT01.pdfFile size 1167 kBChecksum SHA-512
8906d95f030e06ad8655b84cd70fc64eedeea760b507c9ae6d47be2585fc1c4f5fe43efde6e89bd698526c4015f88318c92b73beaa3a42bb9181aa861b13ef21
Type fulltextMimetype application/pdf

Authority records BETA

Almlöf, Heléne

Search in DiVA

By author/editor
Almlöf, Heléne
By organisation
Avdelningen för kemiteknik
Chemical Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 2378 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 962 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf