Nano-coated para-aramid fabric materials: Pull-out, friction, and fracture toughness dynamics

Soft ballistic materials increasingly require lightweight fiber based structure with enhanced interfacial energy dissipation. Although para-aramid fabrics are widely used due to their high tensile strength, limitations in inter-fiber friction and interfacial mechanics constrain their performance under dynamic loading. Prior studies have explored nanoparticle modifications, yet a clear mechanistic understanding linking nanoscale interfacial behavior to macroscopic pull-out responses remains limited. In this study, nanocoated para-aramid fabrics were developed using an iterative compression-assisted deposition method to achieve conformal nanoparticle integration. This work establishes a mechanistic connection between nano-interfacial phenomena and macroscopic energy dissipation during filament pull-out. Morphological (FESEM) and spectroscopic (FT-IR, Raman) analyses confirmed uniform nanoparticle distribution and revealed interfacial bonding features, while thermogravimetric (TGA/DTA) assessments indicated enhanced thermal stability, particularly for nano-boron carbide (n-B₄C, 0.3 wt%) coatings. Significant improvements in rupture force and frictional resistance during single- and multi-yarn pull-outs were attributed to intensified nano–nano and nano–filament interactions, reinforcing interlocking within the crimp-extension regime (Stage I). The fracture toughness of the n-B₄C-coated samples exceeded those of multiwall carbon nanotube (MWCNT, 0.3 wt%), graphene nanoplatelet (GNPs, 0.3 wt%) coatings, and the control fabric by factors of 2.0, 7.51, and 5.71, respectively. Conversely, GNPs introduced a lubricating effect due to their smooth platelet morphology, reducing frictional resistance and facilitating filament slippage. Overall, the findings identify n-B₄C nanocoating as a dominant enhancer of Stage I energy dissipation and provide a compact mechanistic framework for understanding nano-interfacial reinforcement in soft ballistic applications. • Soft para-aramid fabrics were nano-coated via iterative compression method. • Nano-B₄C (0.3 %) improved pull-out strength via interlocking and friction effects. • n-B₄C coatings increased rupture force by enhancing friction at filament crossover. • n-B₄C fabric showed highest toughness, surpassing GNPs, MWCNTs, and controls. • GNPs reduced static friction via lubrication from smooth platelet morphology.