Biodegradable and transparent films with tunable UV-blocking property from Lignocellulosic waste by a top-down approach

As over exposure of the earth to ultraviolet (UV) light and increased amount of petroleum-based plastic waste, biodegradable UV-blocking materials are desired for diverse sustainable applications. The corncob residue from xylitol production (CRXP), as a kind of lignocellulosic waste, is mainly composed of cellulose and lignin. Here, we developed a series of CRXP films through a top-down approach (i.e., tunable delignification and regeneration) without any additional additives. Regenerated films, prepared from treated CRXP with lignin contents of 4.4%–29.7%, had excellent UV-blocking capability: 68.6–99.2% for UVB (290–320 nm) and 47.1–98.2% for UVA (320–400 nm). Moreover, these films showed high optical transparency (50.6–86.6%), enhanced water vapor barrier property (2.17–2.76 × 10^–11 g cm cm⁻² s⁻¹ mmHg⁻¹), great surface hydrophobicity (water contact angle = 73.3°–86.6°), and good thermal stability. Overall, our sustainable UV-blocking films based on CRXP have potential applications in the fields of electronics, food packaging, windshields, and so forth. This study provides new insights into converting lignocellulosic waste directly to high value-added functional bioproducts.