Complete utilization of AlCl3/ZnCl2 aqueous solution to produce lignin-containing cellulose films with controlled properties

The development of lignin-containing cellulose films is of great significance in alleviating plastic pollution. Considering the uniform dispersion of lignin in cellulose films, the AlCl3/ZnCl2 aqueous solution was used to dissolve lignin-containing cellulose fibers for the first time. The lignin-containing cellulose films were produced by dissolving cellulose and well dispersing lignin in the AlCl3/ZnCl2 aqueous solution at room temperature for 20 min and regenerated. The properties of the films were controlled by adjusting the mass fraction of the dissolved lignin-containing cellulose fibers to AlCl3/ZnCl2 aqueous solution. The tensile strength and elongation at break of the lignin-containing cellulose films reached 81.0 MPa and 17.9%, respectively. The films obtained by dissolving 2 wt% lignin-containing cellulose fibers had the highest visible light transmission (63%) and UV blocking (100%). The lignin-containing cellulose film was utterly degraded in soil within 45 days. Moreover, the metal ions in the solution were further used for the in-situ growth of Al-doped ZnO to obtain Al-doped ZnO/lignin-containing cellulose composite films with excellent interface compatibility and antibacterial activity. This work proposed a novel method to produce bio-based composite films with controlled properties.