Synergistic regulation and kinetic mechanism of cellulose-based aramid fiber/phytic acid/nano-silica-aerogel thermal insulation and flame retardant properties

Although cellulose aerogel has the advantages of environmental friendliness and low cost, its lack of thermal stability and fire resistance seriously restricts its engineering applications in high temperature or open fire environments. In this study, cellulose composite aerogels (AF/PA/Si-CA) with excellent thermal stability, thermal insulation, and flame-retardant properties were constructed using cellulose nanoparticles as the matrix. This was achieved through a multistage synergistic strategy involving chemical cross-linking by phytic acid (PA), physical entanglement with aramid fibers (AF), and the incorporation of SiO 2 nanoparticles (Si), thereby improving the flame retardancy and high-temperature thermal stability of the cellulose aerogels. In this study, through molecular dynamics (MD) simulations, given that nitrogen ( N 2 ) occupies 78% of the air volume fraction, its heat transfer and diffusion behavior within the nanopores of the aerogel dominates the overall thermal insulation performance of the material, so the diffusion coefficient and relative concentration distribution characteristics of N 2 molecules are used as the key indexes to quantitatively evaluate the thermal insulation mechanism of cellulose nanogels from a microscopic perspective, and provide theoretical bases for the design of ultra-low thermal conductivity cellulose aerogels. • Proposed a three-dimensional synergistic enhancement mechanism of “chemical cross-linking-physical entanglement-nanofilling”. • Cellulose composite aerogel combines excellent high-temperature thermal insulation with multiple flame retardant self-extinguishing properties. • Combining experiments and molecular dynamics simulations to reveal microscopic insulation mechanisms.