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Following the circular bioeconomy concept, this work studies the potential of an industrial wastepaper residue as an alternative raw material for dissolving pulp‐grade production. Prehydrolysis‐kraft cooking (PHK), elemental chlorine‐free (ECF) bleaching, and acid‐washing treatments were applied to achieve that aim. Considering the high lignin and hemicellulose content of the raw material, it was submitted to PHK pulping to enhance its cellulose content by removing those components. This processing resulted in a remarkable increase of 84 % in pulp Fock reactivity (from 45.6 % to 84.1 %). The dissolution extension and time in solvent systems LiCl/DMAc and NMMO/H2O were discussed regarding the pulp physicochemical properties. The dissolving pulp produced under this work showed great potential as raw material for textile applications, particularly highlighting the innovative process developed to improve its solubility. [ABSTRACT FROM AUTHOR]

The manipulation of hydrogen bonding within protic ionic liquids is conducive to conquering the robust hydrogen bonding interactions in cellulose for its effective dissolution, but it is a great challenge to establish the delicate balance of hydrogen bonding network between solvent and cellulose. Herein, we proposed the concept of "hydrogen bond producers" for urea molecules in 1,1,3,3‐tetramethylguanidinium methoxyacetate acid ([TMGH][MAA]) to enhance the dissolution of cellulose. The optimization of physicochemical properties for [TMGH][MAA] solvent as a function of urea concentration revealed a remarkable increase in cellulose solubility from 13% to 17% (w/w) by adding only 0.25 wt% urea, highlighting the efficiency of [TMGH][MAA] as a powerful solvent for the dissolution of cellulose. The experimental and simulation results verified that the significant improvement on dissolution of cellulose was attributed to the hydrogen bonding interaction of urea molecules with ion pairs and part of free ions, reducing the interference with the active ions bonded to cellulose. Furthermore, the considerable enhancement on comprehensive properties of regenerated cellulose films demonstrated the effectiveness of [TMGH][MAA]/urea solvent. The concept of "hydrogen bond producers" presented here opens a new avenue for significantly enhancing the dissolution of natural cellulose, promoting the sustainable development in large‐scale processing of cellulose. [ABSTRACT FROM AUTHOR]

Cellulose is a biopolymer with numerous advantages that make it an ecological, economical, and high-performing choice for various applications. To fully exploit the potential of cellulose, it is often necessary to dissolve it, which poses a current challenge. The aqueous zinc oxide/sodium hydroxide (ZnO/NaOH/Water) system is a preferred solvent for its rapid dissolution, non-toxicity, low cost, and environmentally friendly nature. In this context, the behavior of cellulose chains in the aqueous solution of ZnO/NaOH and the impact of temperature on the solubility of this polymer were examined through a molecular dynamics simulation. The analysis of the root means square deviation (RMSD), interaction energy, hydrogen bond curves, and radial distribution function revealed that cellulose is insoluble in the ZnO/NaOH solvent at room temperature (T = 298 K). Decreasing the temperature in the range of 273 K to 268 K led to a geometric deformation of cellulose chains, accompanied by a decrease in the number of interchain hydrogen bonds over the simulation time, thus confirming the solubility of cellulose in this system between T = 273 K and T = 268 K. [ABSTRACT FROM AUTHOR]