Synergistic enhancement of crosslinked cellulose nanofiber-lignin composite films toward sustainable biobased materials

초록

The increasing demand for alternatives to petroleum-based films has spurred the quest for high-performance degradable materials. Cellulose, a natural polymer, emerges as an excellent candidate to meet this demand. The development of cellulose films is advanced through crosslinking and additive incorporation. Lignin, a wood by-product with versatile functionalities, serves as a valuable additive. This study explored the synergistic effects of crosslinking cellulose nanofiber (CNF) and lignin. First, non-crosslinked composite films with varying lignin concentrations (NCC-L1, NCC-L5, and NCC-L10) were prepared through solvent casting. Subsequently, the films were immersed in a glutaraldehyde solution with acid catalysts, yielding crosslinked CNF-lignin composite films (GACC-L1, GACC-L5, and GACC-L10). The crosslinking process introduced strong acetal bonds, augmenting the inherent hydrogen bonds of the non-crosslinked films. The results demonstrated that crosslinking significantly enhanced the mechanical properties, thermal stability, crystallinity, and water resistance of the films. Additionally, the integration of lignin conferred UV-blocking and antibacterial properties to the crosslinked films. Notably, GACC-L10 demonstrated superior characteristics, including elevated strength (54.32 MPa), the highest T-max (324.53 degrees C), remarkable antibacterial efficacy (99.9 %), and exceptional transparency (similar to 90 % at 800 nm). Consequently, these films hold promise for a wide range of applications, contributing to the advancement of sustainable materials across diverse industries.

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