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Extended Mercerization Prior to Carboxymethyl Cellulose Preparation
Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemiteknik.
2010 (engelsk)Licentiatavhandling, med artikler (Annet vitenskapelig)
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.

sted, utgiver, år, opplag, sider
Karlstad: Karlstad University , 2010. , s. 51
Serie
Karlstad University Studies, ISSN 1403-8099 ; 2010:22
Emneord [en]
Carboxymethyl cellulose, Mercerization, DS, FT Raman spectroscopy, Filtration ability
HSV kategori
Forskningsprogram
Kemiteknik
Identifikatorer
URN: urn:nbn:se:kau:diva-5947ISBN: 978-91-7063-314-0 (tryckt)OAI: oai:DiVA.org:kau-5947DiVA, id: diva2:326030
Presentation
2010-10-01, 9C 204 (Rejmersalen), Karlstads universitet, KARLSTAD, 13:15 (svensk)
Opponent
Veileder
Tilgjengelig fra: 2010-10-11 Laget: 2010-06-21 Sist oppdatert: 2011-10-04bibliografisk kontrollert
Delarbeid
1. Quantitative analysis of the transformation process of cellulose I → cellulose II using NIR FT Raman spectroscopy and chemometric methods
Åpne denne publikasjonen i ny fane eller vindu >>Quantitative analysis of the transformation process of cellulose I → cellulose II using NIR FT Raman spectroscopy and chemometric methods
2009 (engelsk)Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 16, s. 407-415Artikkel i tidsskrift (Fagfellevurdert) 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.

HSV kategori
Forskningsprogram
Kemiteknik
Identifikatorer
urn:nbn:se:kau:diva-6418 (URN)10.1007/s10570-009-9286-0 (DOI)
Tilgjengelig fra: 2010-09-28 Laget: 2010-09-28 Sist oppdatert: 2017-12-12bibliografisk kontrollert
2. The influence of extended mercerization on some properties of carboxymethyl cellulose (CMC)
Åpne denne publikasjonen i ny fane eller vindu >>The influence of extended mercerization on some properties of carboxymethyl cellulose (CMC)
2012 (engelsk)Inngår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 66, s. 21-27Artikkel i tidsskrift (Fagfellevurdert) 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.

Emneord
alkali, carboxymethyl cellulose, cellulose I, cellulose II, degree of substitution, filterability, mercerization
HSV kategori
Forskningsprogram
Kemiteknik
Identifikatorer
urn:nbn:se:kau:diva-6419 (URN)10.1515/HF.2011.131 (DOI)000298290400003 ()
Tilgjengelig fra: 2010-09-28 Laget: 2010-09-28 Sist oppdatert: 2017-12-12bibliografisk kontrollert
3. Carboxymethyl cellulose produced at different mercerization conditions and characterized by NIR FT Raman spectroscopy and chemometric methods
Åpne denne publikasjonen i ny fane eller vindu >>Carboxymethyl cellulose produced at different mercerization conditions and characterized by NIR FT Raman spectroscopy and chemometric methods
2013 (engelsk)Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 8, nr 2, s. 1918-1932Artikkel i tidsskrift (Fagfellevurdert) Published
Emneord
carboxymethyl cellulose, cellulose backbone structure, degree of substitution, extended mercerization, gel formation, multivariate analytical methods, NIR FT Taman spectroscopy
HSV kategori
Identifikatorer
urn:nbn:se:kau:diva-6420 (URN)000315386400037 ()
Tilgjengelig fra: 2010-09-28 Laget: 2010-09-28 Sist oppdatert: 2017-12-12bibliografisk kontrollert

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