Multifunctional cellulose-based fireproof thermal conductive nanocomposite films assembled by in-situ grown SiO2 nanoparticle onto MXene

•A CNF hybrid film is modified with MXene skeleton featured by SiO2 nanoparticles.•SiO2 nanoparticles are uniformly attached to MXene interlaminar by in-situ method.•The formed 3D heat conduction path weakens the interface thermal resistance.•The film exhibits ultrahigh thermal conductivity and distinguished flame resistance. The use of inorganic nanomaterials as “building blocks” and organic components as “mortars” to build nanocomposites are particularly well-suited to optimize the performance of composites. Here, based on nacre-inspired thought, a novel strategy of fabricating a steady and function tunable three-dimensional MXene thermal conductive cross-linking network skeleton featured by silica (SiO2) nanoparticles bridge was reported, which is constructed in the carboxymethylated cellulose nanofibril (CNF) nanocomposites for facilitating thermal management capability property. Benefited from the strong hydrogen bonding interactions, the thermal conductive fillers of SiO2@MXene are able to uniformly disperse and reduce the agglomeration. SiO2 nanoparticles are uniformly attached to the MXene interlaminar by in-situ method, which is crucial to provide fast conduction channel for heat. The maximum in-plane thermal conductivity value of the SiO2@MXene/CNF nanocomposite film increased form 5.0 W·m−1·K−1 to 26.4 W·m−1·K−1 with introducing 2 wt% SiO2 nanoparticles, accompanied by 5.28 times higher than that of pure CNF film and 436% increase in in-plane conductivity, which indicates that SiO2 nanoparticles are bridged to each thermal transport paths to reduce the interface thermal resistance within CNF-based nanocomposite film. In addition, the cooperative interaction effect of MXene nanosheets and SiO2 nanoparticles in constructing the controllable structural of cross-link framework is contributed to conspicuous improvement of thermal conductivity and flame retardancy. It is worth noting that the effective protective layer formation of SiO2 nanoparticles after the combustion process, simultaneously thermal stability at high temperature which with residue yield (88.70 wt%) of the nanocomposite film, and achieved for a distinguished flame resistance in practical application. Bioinspired thought engineering has become an emerging and promising thought, this type of multifunctional nanocomposite film is highly promising to be a competitive candidate in the fireproof thermal management field and provides an excellent platform for preparing assembled by other p