Nano-fumed silica coated novel cellulosic okra fabrics with enhanced hydrophobic, mechanical and thermal properties for high performance bio-composite applications

The hydrophilic property of lignocellulosic fibers is the main obstacle to improve the performance of structural bio-composites. To effectively utilize such fibers in high-performance composites, their hydrophobicity must be significantly increased. This study presents the hydrophobicity enhancement of okra woven fabric (OWF) by the application of hydrophobic nano-fumed silica (NFS) coating. Different concentrations of NFS were investigated, and SEM analysis confirmed that 1% NFS coated OWF presented the greatest quantity of nanoparticle deposition. The 1% NFS treated OWF exhibited the highest water contact angle of 137.2 ± 1° (~ 148% increased than uncoated fabric) and the greatest tensile strength of 21.85 ± 1.64 MPa in the warp direction and 15.66 ± 1.73 MPa in the weft direction (~ 46.35% and ~ 42.75% respectively superior to uncoated one). The TGA analysis demonstrated that the thermal characteristics have also been enhanced by NFS coating. The interaction between NFS and OWF has been investigated using FTIR analysis, while their elemental composition has been assessed using EDX and XPS techniques.