Cellulose Membranes from Cellulose CO₂‑Based\nReversible Ionic Liquid Solutions

Abstract

Regenerated cellulose membranes (RCMs) were prepared from cellulose\nsufficiently dissolved in [TMGH]₂⁺[OOCOCH₂CH₂OCOO]^2–/DMSO (X_ILS = 0.2, X_ILs is the mole fraction of reversible ionic\nliquids in the mixed solvents) mixed solution under mild conditions\n(50 °C, 3 h, <i>P</i>_CO₂ = 0.2\nMPa) using different coagulation baths of ethanol, methanol, NaOH,\nand H₂SO₄ aqueous solutions. The structure and\nproperties of these membranes were characterized using various characteristic\ntechnologies. The membrane regenerated from ethanol exhibited good\nthermostability and mechanical, water vapor, and oxygen barrier properties\nwith a tensile strength of 56.2 MPa, a tensile strain of 20.4%, an\nexcellent water vapor permeability of 8.7 × 10^–3 g μm/m² day kPa, and an oxygen permeability (OP)\nof 4.087 cm³ μm/m² day atm. The membranes\nregenerated from aqueous solutions of alkali and acid have an OP that\ntends to zero. This study provides a novel dissolving strategy to\nprepare cellulose membranes that have potential applications in the\npackaging, food, and agricultural industries.