Environment-friendly, high-performance cellulose nanofiber-vanillin epoxy nanocomposite with excellent mechanical, thermal insulation and UV shielding properties

With the increased demand for biobased epoxy thermosets as an alternative to petroleum-based materials in various fields, developing environment-friendly and high -performance natural fiberbiobased epoxy nanocomposites is crucial for industrial applications. Herein, an environmentfriendly nanocomposite is reported by introducing cellulose nanofiber (CNF) in situ interaction with lignin-derived vanillin epoxy (VE) monomer and 4, 4 ´-diaminodiphenyl methane (DDM) hardener that serves as a multifunctional platform. The CNF-VE nanocomposite is fabricated by simply dispersing the CNF suspension to the VE and DDM hardener solution through the in-situ reaction, and its mechanical properties and thermal insulation behavior, wettability, chemical resistance, and optical properties are evaluated with the CNF weight percent variation. The welldispersed CNF-VE nanocomposite exhibited high tensile strength (-127.78 +/- 3.99 MPa) and strain-at-break (-16.49 +/- 0.61 %), haziness (-50 %) and UV-shielding properties. The in situ loading of CNF forms covalent crosslinking with the VE and favors improving the mechanical properties along with the homogeneous dispersion of CNF. The CNF-VE nanocomposite also shows lower thermal conductivity (0.26 Wm � 1K-1) than glass. The environment-friendly and high -performance nanocomposite provides multiple platforms and can be used for building materials.