Direct production of regenerated cellulose films from pretreated corn stover using NMMO/water: Effects of pretreatment and crosslinking on film properties

Although the fabrication of regenerated cellulose (RC) films from highly purified cellulose has been extensively studied, few efforts have explored their direct production from chemically pretreated biomass with varying lignin and xylan contents. This study examines the preparation of RC films from corn stover (CS) using N-methylmorpholine-N-oxide (NMMO)/water as the solvent, focusing on the effects of chemical pretreatments and crosslinking on film properties. RC films were prepared from CS subjected to five pretreatment methods: dilute acid, dilute alkali, sodium chlorite (SC)/acetic acid (AA) oxidation, acid-catalyzed γ-valerolactone organosolv, and lactic acid-based deep eutectic solvent. The resulting films were evaluated for chemical composition and degree of polymerization (DP), and these parameters were correlated with visual transparency, mechanical strength, wettability, barrier properties, and biodegradability. Crosslinking with the green reagent 1,4-butanediol diglycidyl ether was employed to further enhance performance. The results show that pretreatment-induced changes in lignin, xylan, and DP significantly influence film properties, while crosslinking markedly increases tensile strength and water-vapor resistance without compromising biodegradability. Among the crosslinked samples , the crosslinked RC films derived from SC/AA-pretreated CS exhibited superior transparency, a tensile strength of 16.90 MPa, the lowest water contact angle of 34.33° and the highest water vapor barrier properties. These findings demonstrate that strategic pretreatment and crosslinking enable the production of sustainable RC films with tunable properties, offering an eco-friendly alternative to petroleum-based materials.