Stable, metastable and unstable cellulose solutions

Research output: Contribution to journalArticle

Abstract

We have characterized the dissolution state of microcrystalline cellulose (MCC) in aqueous tetrabutylammonium hydroxide, TBAH(aq), at different concentrations of TBAH, by means of turbidity and small-angle X-ray scattering. The solubility of cellulose increases with increasing TBAH concentration, which is consistent with solubilization driven by neutralization. When comparing the two polymorphs, the solubility of cellulose I is higher than that of cellulose II. This has the consequence that the dissolution of MCC (cellulose I) may create a supersaturated solution with respect to cellulose II. As for the dissolution state of cellulose, we identify three different regimes. (i) In the stable regime, corresponding to concentrations below the solubility of cellulose II, cellulose is molecularly dissolved and the solutions are thermodynamically stable. (ii) In the metastable regime, corresponding to lower supersaturations with respect to cellulose II, a minor aggregation of cellulose occurs and the solutions are kinetically stable. (iii) In the unstable regime, corresponding to larger supersaturations, there is macroscopic precipitation of cellulose II from solution. Finally, we also discuss strong alkali solvents in general and compare TBAH(aq) with the classical NaOH(aq) solvent.

Details

Authors
  • Marta Gubitosi
  • Pegah Nosrati
  • Mona Koder Hamid
  • Stefan Kuczera
  • Manja A. Behrens
  • Eric G. Johansson
  • Ulf Olsson
Organisations
External organisations
  • Lund University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Chemistry

Keywords

  • Cellulose aggregation, Cellulose dissolution, Cellulose regeneration, Small-angle x-ray scattering, Strong alkali solvents, Tetrabutylammonium hydroxide
Original languageEnglish
Article number170487
JournalRoyal Society Open Science
Volume4
Issue number8
Publication statusPublished - 2017 Aug 30
Publication categoryResearch
Peer-reviewedYes