Enhancing the static and dynamic mechanical behaviours of vinyl ester matrix using surface modified luffa fibers

Abstract

This study focuses on enhancing the static and dynamic mechanical behaviours of vinyl ester matrix using surface modified Luffa fibers. The density of Luffa fiber, which belongs to Cucurbitaceae family, is 1.2 g/cc. The Luffa (Ridge gourd) vegetable was dried in sun-light and the required fiber layers were then obtained by using manual extraction process. The fiber layers were then treated with alkali (5% of NaOH) solution at ambient temperature (28o C) for 24 h. From the SEM images, it can be inferred that the chemical treatment did not degrade the fiber surface and retained its reinforcing nature. The Luffa fiber reinforced vinyl ester composites were developed by hand layup technique by varying the number of fiber layers (1, 2 and 3). The morphological and mechanical behaviours of the developed composites were analyzed as per ASTM standards and compared with pure resin. The static and dynamic mechanical properties of vinyl ester composites exhibited significant improvement with fiber surface treatment and increase in number of fiber layers. Among the different composites tested, the composite specimen with three layers of alkali treated fiber exhibited the highest tensile strength (18.88 MPa) compared to untreated fibers (16.83 MPa). The improvement in properties of Luffa fiber reinforced composites can be attributed to the removal of lignin and waxy substances from the fiber by chemical treatment, which was confirmed by SEM. The obtained results indicate that composites reinforced with three layers of surface modified Luffa fibers showed overall improvement in static and dynamic mechanical behaviours.