Diffusion in Ionic Liquid-Cellulose Solutions during Coagulation in Water: Mass Transport and Coagulation Rate Measurements
2017 (English)In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 50, no 21, p. 8707-8719Article in journal (Refereed) Published
Abstract [en]
This article describes central features of the mass transport during the coagulation in water of cellulose-1-ethyl-3-methylimidazoium acetate ([C2mim][OAc]) solutions, namely, that the diffusivities are mainly affected by the relative concentrations of water and [C2mim][OAc], that the concentration of cellulose does not affect diffusivities and coagulation rates, that the diffusivities of low-Mw compounds are similar to those in aqueous [C2mim][OAc] solutions without macromolecules, that the polymer concentration is diluted by the large influx of coagulant causing a positive net mass gain, NMG, from diffusive fluxes, and that such NMG, although observed only as a function in time, is also a function in space that has local peaks significantly higher than the mean NMG value. The conclusion from the first three findings was that the diffusion advances through a liquid phase which possesses a continuous pore network and most of the volume. The precipitated cellulose is concentrated into fibrils whose inhibitive effect on the diffusion of small molecules through the surrounding phase is marginal. This key understanding about mass transport during coagulation also simplifies numerical modeling significantly.
Place, publisher, year, edition, pages
2017. Vol. 50, no 21, p. 8707-8719
Keywords [en]
Cellulose, Diffusion, Ionic liquids, Cellulose solutions, Coagulation rate, Diffusive flux, Inhibitive effects, Polymer concentrations, Pore networks, Relative concentration, Small molecules, Coagulation
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:ri:diva-33153DOI: 10.1021/acs.macromol.7b01594Scopus ID: 2-s2.0-85034111987OAI: oai:DiVA.org:ri-33153DiVA, id: diva2:1178919
2018-01-312018-01-312023-06-08Bibliographically approved