Characterisation of the undissolved residuals in CMC-solutions

Jardeby, Kristina; Lennholm, Helena; Germgård, Ulf

doi:10.1023/b:cell.0000025390.81603.40

Cited by 16 publications

(16 citation statements)

References 6 publications

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“…It is instead believed that it is mainly the properties of the cellulose and the hemicellulose in the fibres that influence the swelling of the fibres and therefore the DS value of the residuals. The influence of pulp viscosity and hemicellulose content in the fibres on the swelling properties was reported in earlier publications (Jardeby et al 2004(Jardeby et al , 2005.…”

Section: Properties Of the Undissolved Residualsmentioning

confidence: 72%

“…In earlier work (Jardeby et al 2004(Jardeby et al , 2005, we suggested that the undissolved residuals in CMC were caused by wood cells that react more slowly during the etherification due to their larger dimensions or to a denser structure. It was also assumed that the slower reaction was associated with thick-walled wood cells and that these cells were less accessible for chemical penetration.…”

Section: Introductionmentioning

confidence: 94%

“…When cellulosic material is reacted with chloroacetic acid, some of the material may not be completely transferred to CMC during the reaction, so that unreacted wood cells or fibres and gel particles may remain in the CMC (Jardeby et al 2004(Jardeby et al , 2005. The presence of these undissolved residuals decreases the CMC quality, since they give colour and increase the light scattering of the otherwise clear solution when CMC is dissolved in water.…”

Section: Introductionmentioning

confidence: 99%

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The influence of fibre wall thickness on the undissolved residuals in CMC solutions

et al. 2005

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An industrial calcium sulfite pulp was fractionated in a hydrocyclone to four fractions that differed in dimensions and composition due to differences in density. The intention was to investigate whether the fibre dimensions had any influence on the properties of carboxymethyl cellulose (CMC) produced from the fractions and especially how the properties of the unreacted material differed. It was surprisingly found that the fraction containing thin-walled fibres gave CMC and dissolved residuals in the CMC-solution that had the lowest degree of substitution (DS). It was therefore believed that the thin-walled fibres were collapsed and more closely bound in the fibre network after drying of the pulp and that this impeded the chemical diffusion in the subsequent CMC-process, i.e. the diffusion of the CMC-chemicals into the cell wall was slower. There was thus a correlation between thinner fibres and a lower degree of substitution for CMC made from such fibres. It was also found that tick-walled fibres had a higher degree of substitution than the thin-walled fibres but that the highest degree of substitution was obtained if a mixture of thin-and thickwalled fibres were used.

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Section: Properties Of the Undissolved Residualsmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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The influence of fibre wall thickness on the undissolved residuals in CMC solutions

et al. 2005

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“…It has been reported earlier that aggregates of non-substituted or poorly substituted regions may appear as highly swollen opaque or transparent macrogel particles (Rinaudo et al 2000) and that insoluble fractions of CMC mainly consist of low substituted cellulose segments (Jardeby et al 2004). At low DS, when large regions of unsubstituted CMC are present, it has been observed that a gel structure may appear in the CMC solution (Stigsson et al 2008).…”

Section: The Gel Fraction In the Cmc Water Solutionsmentioning

confidence: 94%

“…Lower NaOH concentration and higher temperature in the mercerization stage also increased the filtration resistance, probably due to a more uneven substitution along the cellulose backbone. Jardeby et al (2004) have shown by use of Fourier Transform, FT, Infrared (IR) spectroscopy that carboxymethylation of mercerized spruce sulfite pulp usually results in a substantial insoluble fraction, i.e. a gel that mainly consists of low-substituted cellulose segments.…”

Section: Introductionmentioning

confidence: 99%

Carboxymethyl Cellulose Produced at Different Mercerization Conditions and Characterized by NIR FT Raman Spectroscopy in Combination with Multivariate Analytical Methods

2013

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aCarboxymethyl cellulose (CMC) is produced commercially in a two-stage process consisting of a mercerization stage followed by an etherification stage. In this work, extended mercerization stages were used when producing CMC from a spruce dissolving pulp. Near infra-red (NIR) Fourier transform (FT) Raman spectroscopy was used to analyse the molecular structures of the CMC and the gel fractions formed in the CMC preparation. Three different CMC groups were obtained, representing backbone structures of cellulose I, cellulose II, and amorphous cellulose. By applying principal component analyses (PCA) to the spectral data, two CMC classes were identified with different degrees of substitution (DS). Thus, a low degree of substitution was obtained in the CMC if the alkaline concentration in the mercerization stage was only 9.0%, and the backbone structure was cellulose I or II. However, if the alkaline concentration was higher (18.25% or 27.5%), then the degree of substitution in the CMC was also higher, and the backbone structure was more amorphous.

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High efficiency antimicrobial cellulose‐based nanocomposite hydrogels

Abou-Yousef

Kamel

2015

J of Applied Polymer Sci

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Carboxymethyl cellulose hydrogels were developed through crosslinking process using maleic, succinic, or citric acids. The swelling capacities of the obtained hydrogels have been controlled through variation of the crosslinking reaction conditions. Further enhancement of the swelling properties was achieved by additional blending step of the carboxymethyl cellulose with polyethylene glycol. Biofunctionalization of the hydrogels was achieved through "in situ" incorporation of the silver nanoparticles during the crosslinked reaction. Chemical structure verifications and morphological characterizations of the hydrogels were performed using FTIR, XRD, EDX, and SEM analyses. Finally, the antimicrobial activity of the loaded silver hydrogels against G1ve, G2ve, and yeast Candida albicans was demonstrated.

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Characterisation of the undissolved residuals in CMC-solutions

Cited by 16 publications

References 6 publications

The influence of fibre wall thickness on the undissolved residuals in CMC solutions

The influence of fibre wall thickness on the undissolved residuals in CMC solutions

Carboxymethyl Cellulose Produced at Different Mercerization Conditions and Characterized by NIR FT Raman Spectroscopy in Combination with Multivariate Analytical Methods

High efficiency antimicrobial cellulose‐based nanocomposite hydrogels

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