LAUSR

Abstract Luffa fibers were silane functionalized using varied concentrations of 3-aminopropyl trimethoxysilane (APTMS) in methanol solution to investigate the relationship between the concentration of silanizing agent and the effective degree of silanization of luffa fibers. The aim of the present work was to identify the optimal silane concentration to adequately functionalize the luffa fibers and to investigate its influence on the properties of luffa-epoxy composites. The degree of silanization was controlled by varying the weight ratios of fiber and APTMS (1:0.5, 1:1, 1:1.5, and 1:2). The optimal degree of silanization was confirmed by testing the mechanical, thermal, and flammable properties of functionalized luffa fiber-filled epoxy matrix composites. The composite with 1:1.5 w/w silane functionalization exhibited a maximum tensile strength of 18.4 ± 0.94 MPa. The interfacial adhesion of the prepared samples is investigated through morphological studies. Thermal studies indicated that thermal stability increased with an increase in silanization. TGA analysis revealed that the silane treatment improved the thermal profile of the composites with initial degradation above 240 °C. The storage modulus of composites decreased with an increase in temperature with a 3-stage pattern of the slope. The storage modulus and Tg increased with an increase in silanization degree and the loss modulus peak shifted towards higher temperature with the increase in silanization. Flame retardant studies show that the optimized composite exhibits V-1 rating suggesting the suitability of the prepared composite for various applications.