Preparation of a rough hydrophobic surface on jute fibers via silica hydrosol modification and properties of fiber-reinforced polylactic acid composites

Abstract

Scoured jute fiber was modified with silica hydrosol and then mixed with polylactic acid to form bio-based fiber-reinforced composites. The effects of modification methods on the morphology and hydrophobicity of the fibers, as well as the tensile strength and fracture structure of the composites were studied. Also, the influence of sodium hydroxide concentration, MTMOS concentration, and numbers of dipping steps on the tensile strength of the composites were examined. The results indicated that silica hydrosol condensation could be used to prepare a smooth hydrophobic surface on modified fibers, while a rough hydrophobic surface could be prepared when alkaline treatment was carried out onto the surface of incompletely condensed silica hydrosol film. Rough hydrophilic fibers revealed poor interfacial compatibility and adhesion strength. Smooth hydrophobic surfaces improved interfacial compatibility and dispersibility of the fibers in hydrophobic matrix, whereas a rough hydrophobic structure further improved the adhesion strength through mechanical interlock. The data illustrated that morphology of the silica hydrosol modified fiber surface depended on the alkaline treatment conditions and amounts of adsorbed silica hydrosol, while the effect of MTMOS precursor concentration was negligible.