Competing forces during cellulose dissolution: From solvents to mechanisms

Medronho, Bruno; Lindman, Björn

doi:10.1016/j.cocis.2013.12.001

Cited by 269 publications

(223 citation statements)

References 77 publications

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“…However, in light of the lack of frustration in aqueous systems (Medronho et al 2012), this appears unlikely. An alternative explanation for the presence of charge on the cellulose chains is provided by the recent observation that cellulose is deprotonated in aqueous alkali (Bialik et al 2016), as anticipated by Lindman et al (Medronho and Lindman 2014;Alves et al 2015). Thus, we argue that only the role of the TBA þ cation is similar between the TBAAc/DMSO and TBAH/water solvent system; the primary driving forces for cellulose dissolution are distinct.…”

Section: Resultsmentioning

confidence: 87%

On the dissolution of cellulose in tetrabutylammonium acetate/dimethyl sulfoxide: a frustrated solvent

Idström¹,

Gentile

Gubitosi

et al. 2017

Cellulose

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We have found that the dissolution of cellulose in the binary mixed solvent tetrabutylammonium acetate/dimethyl sulfoxide follows a previously overlooked near-stoichiometric relationship such that one dissolved acetate ion is able to dissolve an amount of cellulose corresponding to about one glucose residue. The structure and dynamics of the resulting cellulose solutions were investigated using small-angle X-ray scattering (SAXS) and nuclear magnetic resonance techniques as well as molecular dynamics simulation. This yielded a detailed picture of the dissolution mechanism in which acetate ions form hydrogen bonds to cellulose and causes a diffuse solvation sheath of bulky tetrabutylammonium counterions to form. In turn, this leads to a steric repulsion that helps to keep the cellulose chains apart. Structural similarities to previously investigated cellulose solutions in aqueous tetrabutylammonium hydroxide were revealed by SAXS measurement. To what extent this corresponds to similarities in dissolution mechanism is discussed.

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Section: Resultsmentioning

confidence: 87%

On the dissolution of cellulose in tetrabutylammonium acetate/dimethyl sulfoxide: a frustrated solvent

Idström¹,

Gentile

Gubitosi

et al. 2017

Cellulose

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“…Raw wastewater contains dissolved cellulose fibers which are soluble in high alkaline solutions. [18] This could be the reason for the aforementioned negative flux decline recovery after acidic cleaning, and further investigation should be conducted.…”

Section: Flux Recoverymentioning

confidence: 99%

“…The aqueous alkali systems do not completely disrupt the crystalline structure of the cellulose and the solubility is limited to cellulose with low degree of polymerization. [18] It is assumed that the remaining organic compounds in the 1 kDa permeate refer to surfactants from the wetting agent and dissolved cellulose molecules. According to the expectations, pH value, TDS and conductivity levels were approximately the same for 1 and 2 kDa membrane permeate because the membrane pores are too large to maintain the reflected dissolved constituents such as sodium hydroxide and surfactants.…”

Section: Membrane Characterizationmentioning

confidence: 99%

Effect of operating conditions on the performances of multichannel ceramic UF membranes for textile mercerization wastewater treatment

Avdičević

Košutić

Dobrović

2016

Environmental Technology

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Textile wastewaters are rated as one of the most polluting in all industrial sectors, and membrane separation is the most promising technology for their treatment and reuse of auxiliary chemicals. This study evaluates the performance of three types of tubular ceramic ultrafiltration membranes differing by mean pore size (1, 2 and 500 kDa) treating textile mercerization wastewater from a textile mill at different operating conditions: cross-flow velocity (CFV) and temperature. Acceptable results were obtained with 1 kDa ceramic membrane, with rejection efficiencies 92% for suspended solids, 98% for turbidity, 98% for color and 53% for total organic carbon at 20°C and 3 m s −1 CFV. Highest fouling effect was observed for 500 kDa membrane and lowest CFV. According to the observed results, 1 kDa membrane could be used for the treatment of wastewater from the textile mercerization process in terms of permeate quality. ARTICLE HISTORY

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“…Among the different ways of disassembly, dissolution enables to separate the polymer chains from each other and produce molecular ''bricks'' for construction of novel materials (Trygg 2015). For a given semicrystalline polymer, such as cellulose, the chains are more in the regular, arrangement and it is rather difficult to unfold the well-packed chains into a disordered state in solution (Lindman et al 2010;Medronho and Lindman 2014). Over decades the hydrogen bonds network in cellulose has been claimed as the reason of the crystalline structure of cellulose and the limitations in cellulose dissolution (Bodvik et al 2010;Zhang et al 2002), while the amphiphilic nature of cellulose has probably been underestimated (Medronho et al 2012.…”

Section: Introductionmentioning

confidence: 99%

Spherical nanocomposite particles prepared from mixed cellulose–chitosan solutions

et al. 2016

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Novel cellulose-chitosan nanocomposite particles with spherical shape were successfully prepared via mixing of aqueous biopolymer solutions in three different ways. Macroparticles with diameters in the millimeter range were produced by dripping cellulose dissolved in cold LiOH/urea into acidic chitosan solutions, inducing instant co-regeneration of the biopolymers. Two types of microspheres, chemically crosslinked and non-crosslinked, were prepared by first mixing cellulose and chitosan solutions obtained from freeze thawing in LiOH/KOH/urea. Thereafter epichlorohydrin was applied as crosslinking agent for one of the samples, followed by water-inoil (W/O) emulsification, heat induced sol-gel transition, solvent exchange, washing and freeze-drying. Characterization by X-ray photoelectron spectroscopy, total elemental analysis, and Fourier transform infrared spectroscopy confirmed the prepared particles as being true cellulose-chitosan nanocomposites with different distribution of chitosan from the surface to the core of the particles depending on the preparation method. Field emission scanning electron microscopy and laser diffraction was performed to study the morphology and size distribution of the prepared particles. The morphology was found to vary due to different preparation routes, revealing a core shell structure for macroparticles prepared by dripping, and homogenous nanoporous structure for the microspheres. The non-crosslinked microparticles exhibited a somewhat denser structure than the crosslinked ones, which indicated that crosslinking restricts packing of the chains before and under regeneration. From the obtained volume-weighted size distributions it was found that the crosslinked microspheres had the highest median diameter. The results demonstrate that not only the mixing ratio and distribution of the two biopolymers, but also the morphology and nanocomposite particle diameters are tunable by choosing between the different routes of preparation.

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Competing forces during cellulose dissolution: From solvents to mechanisms

Cited by 269 publications

References 77 publications

On the dissolution of cellulose in tetrabutylammonium acetate/dimethyl sulfoxide: a frustrated solvent

On the dissolution of cellulose in tetrabutylammonium acetate/dimethyl sulfoxide: a frustrated solvent

Effect of operating conditions on the performances of multichannel ceramic UF membranes for textile mercerization wastewater treatment

Spherical nanocomposite particles prepared from mixed cellulose–chitosan solutions

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