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Östberg, Linda
Publications (10 of 12) Show all publications
Almlöf Ambjörnsson, H., Östberg, L., Schenzel, K., Larsson, P. T. & Germgård, U. (2014). Enzyme pretreatment of dissolving pulp as a way to improve the following dissolution in NaOH/ZnO. Holzforschung, 68(4), 385-391
Open this publication in new window or tab >>Enzyme pretreatment of dissolving pulp as a way to improve the following dissolution in NaOH/ZnO
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2014 (English)In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 68, no 4, p. 385-391Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Walter de Gruyter, 2014
National Category
Other Natural Sciences
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-26959 (URN)10.1515/hf-2013-0070 (DOI)000335650900003 ()
Available from: 2013-04-16 Created: 2013-04-16 Last updated: 2017-12-06Bibliographically approved
Östberg, L. & Germgård, U. (2013). Some aspects on the activation of dissolving pulps and the influence on the reactivity in a following viscose stage. Cellulose Chemistry and Technology, 47(3-4), 165-169
Open this publication in new window or tab >>Some aspects on the activation of dissolving pulps and the influence on the reactivity in a following viscose stage
2013 (English)In: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 47, no 3-4, p. 165-169Article in journal (Refereed) Published
Abstract [en]

It was found that, for a dissolving pulp, an enzymatic pre-treatment with an endoglucanase prior to viscose preparation did not change the correlation between the gamma number of the viscose dope and the carbon disulphide charge. Thus, the pulp stoichiometry, or reactivity, was not changed by an endoglucanase pre-treatment. It has nevertheless previously been found that the pulp reactivity, measured either by Fock's test or as the filter clogging value (Kw), increased for the same type of enzyme pre-treatment. Thus, the pulp reactivity seems to be influenced by the analysis method employed.

Keywords
dissolving, pulp, DP, enzyme, gamma number, reactivity, viscose
National Category
Paper, Pulp and Fiber Technology
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-27134 (URN)000321403800003 ()
Available from: 2013-04-30 Created: 2013-04-30 Last updated: 2017-12-06Bibliographically approved
Östberg, L., Kvarnlöf, N. & Germgård, U. (2013). The hemicellulose content in two chemical pulps and its influence on Fock´s test and the gamma number of the resulting viscose dope. Nordic Pulp & Paper Research Journal, 28(3), 377-380
Open this publication in new window or tab >>The hemicellulose content in two chemical pulps and its influence on Fock´s test and the gamma number of the resulting viscose dope
2013 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 28, no 3, p. 4p. 377-380Article in journal (Refereed) Published
Publisher
p. 4
Keywords
Cellulose, Cold Caustic Extraction, Gamma Number, Hemicelluloses, Viscose
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-34705 (URN)10.3183/NPPRJ-2013-28-03-p377-380 (DOI)
Available from: 2014-12-03 Created: 2014-12-03 Last updated: 2019-09-19Bibliographically approved
Östberg, L., Håkansson, H. & Germgård, U. (2012). Some aspects of the reactivity of pulp intended for high-viscosity viscose. BioResources, 7(1), 743-755
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, p. 743-755Article 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.

Keywords
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
Östberg, L. (2012). Some Aspects on Pulp Pre-treatment Prior to Viscose Preparation. (Licentiate dissertation). Karlstad: Karlstad University Press
Open this publication in new window or tab >>Some Aspects on Pulp Pre-treatment Prior to Viscose Preparation
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. p. 44
Series
Karlstad University Studies, ISSN 1403-8099 ; 2012:23
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-13272 (URN)978-91-7063-427-7 (ISBN)
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
Germgård, U., Östberg, L. & Håkansson, H. (2011). Enzyme Activation of Pulp and its Influence on the Gamma Number of Viscose. Paper presented at Poster presented at the IAWS 2011 conference, Augusti 31 - September 2, 2011. Paper presented at Poster presented at the IAWS 2011 conference, Augusti 31 - September 2, 2011.
Open this publication in new window or tab >>Enzyme Activation of Pulp and its Influence on the Gamma Number of Viscose
2011 (English)Conference paper, Published paper (Other (popular science, discussion, etc.))
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-10768 (URN)
Conference
Poster presented at the IAWS 2011 conference, Augusti 31 - September 2, 2011
Available from: 2012-02-08 Created: 2012-02-08 Last updated: 2013-06-12Bibliographically approved
Germgård, U., Östberg, L. & Håkansson, H. (2011). Lab Scale Preparation of High Viscosity Viscose at Karlstad University. Paper presented at Poster presented at the IAWS 2011 conference, Augusti 31 - September 2, 2011. Paper presented at Poster presented at the IAWS 2011 conference, Augusti 31 - September 2, 2011.
Open this publication in new window or tab >>Lab Scale Preparation of High Viscosity Viscose at Karlstad University
2011 (Swedish)Conference paper, Published paper (Other (popular science, discussion, etc.))
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-10769 (URN)
Conference
Poster presented at the IAWS 2011 conference, Augusti 31 - September 2, 2011
Available from: 2012-02-08 Created: 2012-02-08 Last updated: 2013-06-12Bibliographically approved
Östberg, L. (2011). Laboratory Preparation of Viscose. Paper presented at 1st Avancell Conference, October 18-19, 2011, Gothenburg, Sweden.
Open this publication in new window or tab >>Laboratory Preparation of Viscose
2011 (English)Conference paper, Published paper (Refereed)
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-9137 (URN)
Conference
1st Avancell Conference, October 18-19, 2011, Gothenburg, Sweden
Available from: 2012-01-10 Created: 2012-01-10 Last updated: 2012-01-11Bibliographically approved
Östberg, L. & Germgård, U. (2011). Some Aspects of the Reactivity of Pulp Intended for High-Viscosity Viscose: Influence on the Reactivity and the Gamma Number. Paper presented at Paper Published in PaPSaT-FPIRC Summer Conference in Lappenranta 2011. Paper presented at Paper Published in PaPSaT-FPIRC Summer Conference in Lappenranta 2011.
Open this publication in new window or tab >>Some Aspects of the Reactivity of Pulp Intended for High-Viscosity Viscose: Influence on the Reactivity and the Gamma Number
2011 (English)Conference paper, Published paper (Other (popular science, discussion, etc.))
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-10930 (URN)
Conference
Paper Published in PaPSaT-FPIRC Summer Conference in Lappenranta 2011
Available from: 2012-02-08 Created: 2012-02-08 Last updated: 2013-06-12Bibliographically approved
Germgård, U., Håkansson, H. & Östberg, L. (2009). Activation of Dissolving Pulp with Enzymes Prior to Preparation of High Viscosity Viscose. Paper presented at The 4th Workshop on Cellulose, Regenerated Cellulose and Cellulose Derivatives at Karlstad University, Karlstad, Sweden, November 17-18, 2009. Paper presented at The 4th Workshop on Cellulose, Regenerated Cellulose and Cellulose Derivatives at Karlstad University, Karlstad, Sweden, November 17-18, 2009.
Open this publication in new window or tab >>Activation of Dissolving Pulp with Enzymes Prior to Preparation of High Viscosity Viscose
2009 (English)Conference paper, Published paper (Other (popular science, discussion, etc.))
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-9897 (URN)
Conference
The 4th Workshop on Cellulose, Regenerated Cellulose and Cellulose Derivatives at Karlstad University, Karlstad, Sweden, November 17-18, 2009
Available from: 2012-02-08 Created: 2012-02-08 Last updated: 2013-06-12Bibliographically approved
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