Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • 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
Some Aspects on Pulp Pre-treatment Prior to Viscose Preparation
Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. (Massateknik)
2012 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Large amounts of carbon disulphide are consumed in the conventional production of viscose. Until a novel, eco-friendly, wood-based process for the production of cellulose textile fibres has been developed and implemented, it is important to try to find ways to improve the conventional viscose process, e.g. in terms of reducing the carbon disulphide requirement of the process. The aim of this thesis was to reduce the amount of carbon disulphide consumed in the preparation of high-viscosity viscose by pre-treating pulps with enzymes. It also aimed at investigating and linking the different measurements of reactivity, i.e. gamma number, Fock reactivity and Kw, and determining the sensitivity of the gamma number to the hemicellulose content of pulp. Reactivity was measured as Fock reactivity and gamma number. The gamma number of viscose solutions remained unchanged when an enzyme stage was used prior to the viscose process. The gamma number analysis was found to be selective not only to cellulose but also to the hemicellulosic material. It was verified that both cellulose and hemicellulose molecules in the pulp material were substituted in the viscose preparation stages, showing that the gamma number of the pulp is due to both substituted cellulose and substituted hemicelluloses. The mechanisms responsible for the Fock reactivity, or the filter-clogging value (Kw) on the one hand and the gamma number on the other, are probably not the same. It was speculated that the analysis method employed in Fock´s test and the filter-clogging value measure the results on a fibre level, whereas the gamma number measures changes mainly on a molecular level. This could explain the difference in the levels of reactivity found in this study.

Place, publisher, year, edition, pages
Karlstad: Karlstad University Press, 2012. , 44 p.
Series
Karlstad University Studies, ISSN 1403-8099 ; 2012:23
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
URN: urn:nbn:se:kau:diva-13272ISBN: 978-91-7063-427-7 (print)OAI: oai:DiVA.org:kau-13272DiVA: diva2:525302
Presentation
2012-06-15, Nyquistsalen 9C203, Universitetsgatan 1, Karlstad, 13:00 (Swedish)
Opponent
Supervisors
Available from: 2012-05-24 Created: 2012-05-07 Last updated: 2012-08-27Bibliographically approved
List of papers
1. Some aspects of the reactivity of pulp intended for high-viscosity viscose
Open this publication in new window or tab >>Some aspects of the reactivity of pulp intended for high-viscosity viscose
2012 (English)In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, no 1, 743-755 p.Article in journal (Refereed) Published
Abstract [en]

The original objective of this study was to reduce the consumption of carbon disulphide in the preparation of high-viscosity viscose by pre-treating two softwood pulps with enzymes prior to the viscose stages. Reactivity can, however, be measured in different ways and the methods used in this study are Fock´s test of the pulp and the gamma number of the viscose solution prior to regeneration. It was found that whilst the reactivity of a pulp that had been subjected to enzyme pretreatment increased according to Fock´s test, it did not increase when the gamma number obtained in a standardized viscose preparation process was used. This unexpected difference that was discovered between the two reactivity tests made it difficult to analyze the impact of the enzyme stage on reactivity; the underlying reasons for the different reactivity results obtained were therefore investigated first. The conclusion that may be drawn from this investigation is that Fock´s test measures the extent to which carbon disulphide reacts with a pulp sample during a standardized test whereas the gamma number measures the resulting degree of xanthate substitution on the cellulose backbone. These two reactivity tests are thus not totally correlated. It was concluded that the gamma number was the more relevant of the two tests since it reflects the dissolution ability of a pulp in the viscose preparation, which is a very basic property of viscose. A higher gamma number also means that the coagulation time in the spinning process is prolonged; this is beneficial as it can be used to increase the tenacity of the viscose fibres. Measuring the reactivity according to Fock´s test, on the contrary, provides more dubious results as the test has no undisputed correlation to the viscose preparation process.

Keyword
Carbon disulphide, endoglucanase, Fock test, Gamma number, Viscose, Xylanase
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-13244 (URN)000304041200058 ()
Available from: 2012-05-07 Created: 2012-05-07 Last updated: 2017-12-07Bibliographically approved
2. Some Aspects on the Reactivity of a Dissolving Pulp when used for Viscose Preparation
Open this publication in new window or tab >>Some Aspects on the Reactivity of a Dissolving Pulp when used for Viscose Preparation
(English)In: O papelArticle in journal (Refereed) Submitted
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-13245 (URN)
Available from: 2012-05-07 Created: 2012-05-07 Last updated: 2013-10-11Bibliographically approved
3. The Influence of the Hemicellulose Content in Dissolving Pulps on the Gamma Number of Viscose Dopes
Open this publication in new window or tab >>The Influence of the Hemicellulose Content in Dissolving Pulps on the Gamma Number of Viscose Dopes
(English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669Article in journal (Refereed) Submitted
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-13246 (URN)
Available from: 2012-05-07 Created: 2012-05-07 Last updated: 2017-12-07Bibliographically approved

Open Access in DiVA

KUS_2012_23(694 kB)1934 downloads
File information
File name FULLTEXT02.pdfFile size 694 kBChecksum SHA-512
7eb4f0280f487e4c71e4e8bda2ee9d4328db2dd255a30f728b04a862d22106eb6029cb3c9346ba33c1604901d8d5aa35408e8e599f40e801de4b77c068969481
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Östberg, Linda
By organisation
Department of Chemical Engineering
Chemical Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 2065 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: 527 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • 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