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Is there a diffusio...
Is there a diffusion of alkali in the activation of dissolving cellulose pulp at low NAOH stoichiometric excess?
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- Albán Reyes, Diana Carolina (författare)
- Umeå universitet,Kemiska institutionen
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- Stridh, Kjell (författare)
- AkzoNobel, Stenungsund, Sverige
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- de Wit, Paul P. (författare)
- AkzoNobel, Arnhem, The Netherlands
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- Sundman, Ola (författare)
- Umeå universitet,Kemiska institutionen
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(creator_code:org_t)
- 2018-11-10
- 2019
- Engelska.
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Ingår i: Cellulose. - : Springer. - 0969-0239 .- 1572-882X. ; 26:2, s. 1297-1308
- Relaterad länk:
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https://doi.org/10.1...
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https://umu.diva-por... (primary) (Raw object)
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https://link.springe...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
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- We conducted a quantitative study, following the degree of activation (i.e. the transformation to alkali cellulose, denoted as DoA) over time for dissolving cellulose pulp treated with different [NaOH] at low NaOH/anhydroglucose unit stoichiometric ratio (denoted as (r) ≤ 2.6). Our quantitative approach was based on Raman spectroscopy data, evaluated by partial least squares regression modelling. The results show strong influence of the (r) on DoA (increasing from DoA= 45% at (r) = 0.8, to DoA = 85% at (r) = 2.6), and its complex dependence on [NaOH]. At (r) = 0.8 the highest DoA (DoA ≳ 60%) was found at 30% [NaOH], while at (r) =1.3 it was found at 20% [NaOH] (DoA ≳ 80%). Although activation of cellulose happens in minutes at the studied temperature (30 °C), it was found that the reaction may be slow when a low (r) is used. A gradual increase of the DoA from ≈ 30% to ≈ 70% in time was seen when samples were activated with 30% [NaOH] at (r) = 0.8. At the same (r), a similar increase of DoA from ≈ 30 % to ≈ 60 % was also observed when 40% [NaOH] was used. Slow diffusion of NaOH through poorly swollen cellulose fibres is proposed as an explanation for this phenomenon. Lastly, solid-state CP/MAS NMR measurements suggest that at a fixed temperature, the Na-Cell allomorph mostly depends on [NaOH]. However, in the transition area between Na-Cell I and Na-Cell II, its influence might be affected by (r).
Ämnesord
- NATURVETENSKAP -- Kemi -- Annan kemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences -- Other Chemistry Topics (hsv//eng)
- TEKNIK OCH TEKNOLOGIER -- Materialteknik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Materials Engineering (hsv//eng)
Nyckelord
- Alkali cellulose
- Activation
- Polymorphs
- Cellulose ether
- Diffusion
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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