Recent advances in regenerated cellulose materials

Aerocellulose: new highly porous cellulose prepared from cellulose-NaOH aqueous solutions

Brief overview on cellulose dissolution/regeneration interactions and mechanisms

Functional Cellulose Beads: Preparation, Characterization, and Applications

Aerocellulose from cellulose–ionic liquid solutions: Preparation, properties and comparison with cellulose–NaOH and cellulose–NMMO routes

Structure of Aqueous Solutions of Microcrystalline Cellulose/Sodium Hydroxide below 0 °C and the Limit of Cellulose Dissolution

It has been reported that cellulose is better dissolved in NaOH-water when a certain amount of urea is added. In order to understand the mechanisms of this dissolution and the interactions between the components, the binary phase diagram of urea/water, the ternary urea/NaOH/water phase diagram and the influence of the addition of microcrystalline cellulose in urea/NaOH/water solutions were studied by DSC. Urea/water solutions have a simple eutectic behaviour with a eutectic compound formed by pure urea and ice (one urea per eight water moles), melting at −12.5 °C. In the urea/NaOH/water solutions, urea and NaOH do not interact, each forming their own eutectic mixtures, (NaOH + 5H2O, 4H2O) and (urea, 8H2O), as found in their binary mixtures. When the amount of water is too low to form the two eutectic mixtures, NaOH is attracting water at the expense of urea. In the presence of microcrystalline cellulose, the interactions between cellulose and NaOH/water are exactly the same as without urea, and urea is not interacting with cellulose. A tentative explanation of the role of urea is to bind water, making cellulose-NaOH links more stable.

The dissolution of microcrystalline cellulose in sodium hydroxide-urea aqueous solutions

The rheological and hydrodynamic properties of cellulose dissolved in (8-9%)NaOH/water and in 1-ethyl-3-methylimidazolium acetate (EMIMAc) were studied and compared. The influence of cellulose type, concentration, solution temperature and presence of additives (in the case of cellulose dissolved in NaOH/water) was investigated. While the dissolution power of NaOH/water decreases with temperature increase and cellulose solutions are gelling, the intrinsic viscosities of cellulose in NaOH/water and in EMIMAc are very close in absolute values and behave in the same way with temperature. This paradox was assumed to be due to the role of water in NaOH/water hydrates.

Magali Egal

Papers

Structure of Aqueous Solutions of Microcrystalline Cellulose/Sodium Hydroxide below 0 °C and the Limit of Cellulose Dissolution

The dissolution of microcrystalline cellulose in sodium hydroxide-urea aqueous solutions

Comparison of Solution-State Properties of Cellulose Dissolved in NaOH/Water and in Ionic Liquid (EMIMAc)