Dissolution of Bamboo Dissolving Pulp Cellulose in Zinc Bromide Hydrate Molten Salt and Its Regenerated Cellulose Membranes with High Strength and Transparency

Abstract Cellulose, owing to its abundance, renewability, and biocompatibility, has emerged as a promising candidate for high-performance and eco-friendly materials. Here, a simple method for preparing a regenerated cellulose membrane was developed by dissolving bamboo dissolving pulp (BDP) in ZnBr2 hydrate molten salt followed by mixing with a small amount of DMSO and then regenerating from ethanol. The influence of different ZnBr2/H2O molar ratio, dissolution temperature, and time on the membrane properties was systematically investigated. When ZnBr2·4H2O was used to dissolve BDP at 80 °C for 15 min, the dissolution performance was optimal, and the membrane 4-BDM80-15 prepared exhibited the highest tensile strength of 107.92 MPa. Moreover, 4-BDM80-15 showed a relatively smooth surface, higher optical transparency (91.2%), and lower water vapor permeability (2.64 × 10−11 g·m−1∙s−1∙Pa−1). Compared with the commercial polypropylene membrane, 4-BDM80-15 exhibited a much lower environmental impact, achieving nearly complete degradation within 35 days. Overall, this study established an effective strategy for the fabrication of high-performance regenerated cellulose membranes, which has significant application potential in the fields of sustainable materials and environmental remediation.