Mass transport during coagulation of cellulose-ionic liquid solutions in different non-solvents
2019 (English) In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, no 16, p. 8525-8541Article in journal (Refereed) Published
Abstract [en]
Abstract: Cellulose can be regenerated from cellulose-ionic liquid (IL) solutions by immersion in water or alcohols. These compounds are potent non-solvents due to their proton-donating ability in hydrogen bonds to IL anions. Although they share this fundamental way of reducing IL solvent quality, coagulation in water is distinctly different from coagulation in alcohols with regard to the microstructures formed and the mechanisms that generate the microstructures. In this study, the possibility of mass-transport effects on microstructures was investigated. The mass-transport of all components: non-solvent (EtOH, 2PrOH), IL ([C2mim][OAc]), and a co-solvent (DMSO), during coagulation was studied. The data was compared to previous data with water as the non-solvent. Results showed that diffusion is essentially limited to a continuous non-solvent-rich phase that is formed during phase separation in all non-solvents. There were also significant differences between non-solvents. For instance, [C2mim][OAc] diffusion coefficients were 6–9 times smaller in 2PrOH than in water, and there were apparent effects from cellulose concentration in 2PrOH that were not observed in water. The differences stem from the interactions between solvent, non-solvents, and cellulose, which can be both mutual and competitive. Weaker [C2mim][OAc]-non-solvent interactions with alcohols give more persistent [C2mim][OAc]-cellulose interactions than with water as the non-solvent, which has consequences for mass-transport. Graphic abstract: [Figure not available: see fulltext.].
Place, publisher, year, edition, pages Springer Netherlands , 2019. Vol. 26, no 16, p. 8525-8541
Keywords [en]
Alcohol, Cellulose, Coagulation, Ionic liquids, Mass transport, Non-solvent, Precipitation, Water, Alcohols, Hydrogen bonds, Mass transfer, Microstructure, Phase separation, Praseodymium compounds, Precipitation (chemical), Cosolvents, Immersion in waters, Liquid solution, Non-solvents, Rich phase, Solvent quality, Transport effects, Solvents
National Category
Natural Sciences
Identifiers URN: urn:nbn:se:ri:diva-39853 DOI: 10.1007/s10570-019-02649-w Scopus ID: 2-s2.0-85070798486 OAI: oai:DiVA.org:ri-39853 DiVA, id: diva2:1347221
Note Funding text 1: Open access funding provided by Chalmers University of Technology. This research would not have been possible without financing from the Södra Skogsägarna Foundation for Research, Development and Education. The scientists at the Swedish NMR Centre in Gothenburg as well as the other partners within the Avancell Project are gratefully acknowledged for their help in this Project. 1 The hydroxyl groups of cellulose cannot be very much stronger hydrogen-bond donors than other alcohols are (e.g. methanol has αα = 0.43 and ethandiol has αα = 0.58).
2019-08-302019-08-302023-06-08 Bibliographically approved