High-strength cellulose films obtained by the combined action of shear force and surface selective dissolution

Cellulose is a promising and advantageous material because it is low-cost, abundant and biodegradable. Nonetheless, dealing with this material is extremely challenging because cellulose cannot dissolve in most solvents or melt at any temperature or pressure in the air owing to strong hydrogen-bonding networks. In this work, a surface selective dissolution with shear force process was proposed to prepare cellulose films with high strength from microcrystalline cellulose powders. The tensile strength reached 94 MPa and the thermal decomposition temperature improved by 64 °C compared with that of regenerated cellulose. A mechanism of surface dissolution and reconnection was proposed to explain the process. The outstanding mechanical property attributes to tight reconnection of the undissolved cores via dissolved surfaces in cellulose powders, and the improved thermal decomposition temperature is due to preserved cellulose Ⅰ crystalline structure of microcrystalline cellulose. We believe that this cost-effective and facile method holds promise for industrial-scaleproduction of cellulose materials.