Load-Bearing and Machining Behavior of Treated Nano-sorghum-Millet-Husk-Biosilica- and Kenaf-Fiber-Reinforced Vinyl Ester Composite

This study investigates the mechanical properties of composites focusing on tensile, flexural, compression strength, Izod impact toughness, hardness, fatigue life, creep resistance, and drilling behavior. The approach involves extracting nano-biosilica from sorghum husk and infusing it with silane-treated kenaf fiber under temperature aging conditions to enhance composite materials’ properties. The reinforcement consists of kenaf fibers (34.2–43.2 µm in diameter) and nano-biosilica prepared from sorghum millet husk via a thermochemical method. Silane treatment enhances the adhesive bonding between the matrix (vinyl ester resin and methyl ethyl ketone peroxide in a 10:1 ratio) and reinforcing agents. Composite fabrication employs a hand layup method with varying concentrations of biosilica (1 vol. %, 3 vol. %, and 5 vol. %) and kenaf fiber. Notably, specimens N2 and M2 exhibited superior performance, with N2 achieving tensile strength of 101 MPa, flexural strength of 123 MPa, compression strength of 159.9 MPa, Izod impact toughness of 4.9 kJ/m², and hardness of 98 Shore-D. Even after undergoing aging at 40 °C and 70% humidity for 30 days, M2 demonstrated remarkable durability to the silane treatment of both fiber and filler with tensile strength of 85 MPa, flexural strength of 117 MPa, compression strength of 143 MPa, Izod impact toughness of 4.2 kJ/m², and hardness of 95 Shore-D. SEM analysis revealed uniform dispersion of filler particles in N2 and M2, highlighting the effectiveness of the silane treatment in enhancing microstructural characteristics and durability. This research underscores the potential of silane-treated kenaf-fiber- and nano-biosilica-reinforced vinyl ester composites for applications requiring enhanced mechanical properties and durability.