Green reinforcement of cellulose fibers: rGO size and loading effects on Lyocell composites from atomistic insight to macroscopic performance

This study investigates the size- and loading-dependent reinforcement effects of reduced graphene oxide (rGO) on Lyocell fibers through a combination of multiscale molecular dynamics (MD) simulations and experimental analysis. Four rGO sheets with distinct lateral sizes were incorporated into a cellulose matrix via NMMO-based dry-jet wet spinning. MD simulations revealed that smaller rGO sheets formed more hydrogen bonds with cellulose chains, enhancing interfacial adhesion and promoting molecular orientation. Experimentally, the composite fiber with 0.5‰ small-sized rGO achieved a 17.8% increase in tensile strength compared to pristine Lyocell (from 4.48 ​cN/dtex to 5.28 cN/dtex), along with improved orientation index and thermal stability. Furthermore, a preliminary solvent recovery test confirmed that such low rGO loading did not impair the recyclability of NMMO, supporting the green and sustainable nature of the process. The synergistic influence of rGO size and loading governs dispersion behavior, hydrogen bonding density, and chain alignment during spinning. These findings provide molecular-level insight into rGO–cellulose interactions and present an environmentally conscious strategy for producing high-performance bio-based composite fibers, with promising applications in technical textiles and sustainable functional materials.