Transparent Cellulose-Based Composite Film with Functional Integration for Potential Agriculture Application

Within the realm of sustainable agriculture, there is a growing focus on the development of biodegradable plastic coverings in response to the adverse environmental impact stemming from contamination by fossil-based plastic film. Herein, a function-integrated cellulose-based composite film was innovatively designed for agricultural insulation applications. Lignocellulosic nanofibers (LCNF) and hollow SiO₂ microspheres are blended to construct LCNF/SiO₂ composite films with multistage nanocavity structures. Meanwhile, the hexadecyltrimethoxysilane modification further promotes the integration of hydrophobic function and the encapsulated function of hollow SiO₂ microspheres in the composite film to form the hydrophobic LCNF/SiO₂ (H-LCNF/SiO₂) composite film. Owing to the small size effect of SiO₂ microspheres and the nanocavity structure, the resulting film exhibits a low thermal conductivity (0.07 ± 0.002 W/(m·K)) and excellent optical properties of the UV–Vis transmission with transparency of over 77% (above 600 nm). Furthermore, H-LCNF/SiO₂ composite film displays acceptable mechanical properties with tensile strength of 56.03 MPa and elongation at a break of 6.10%, respectively. Notably, the composite film acquires excellent flexibility, water-proofing, water vapor permeability, and biodegradable performances, improving agricultural applications. Therefore, this work provides a lignocellulose-based film with functional integration that differs from traditional agricultural films by constructing a hollow structure to achieve thermal protection, with the advantage of being more energy efficient and environmentally friendly, promising potential applications in agriculture.