Nondestructive characterization of epoxy matrix composites reinforced with Luffa lignocellulosic fibers

Abstract

Luffa Cylindrica is a tropical plant from the Cucurbitaceae family, whose fruit becomes very fibrous when fully ripened. The lignocellulosic sponges of Luffa can be suitable for use as reinforcement of epoxy matrix composites, because they have a morphology with spatial 3-D arrangement as well as are eco-friendly materials (biodegradable, and high available) and have economic advantages compared to composites reinforced with synthetic fibers derived from non-renewable sources. Surface modification of the Luffa fibers was carried out by hornification and mercerization methods and was verified by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-Ray Diffraction (XRD). For the fabrication of non-biodegradable composites by hand layup technique, the sponges were impregnated with an epoxy resin based on bisphenol in a metallic mold with dimensions 150×200×3 mm 3 , followed by compression at 5 MPa. The dynamic modulus of the fabricated composites were measured using the nondestructive impulse excitation technique (IET), according to the ASTM E1876 standard. Bar specimens with dimensions 80×25×3 mm 3 of the laminated composites were tested at room temperature, with Sonelastic® (ATCP) equipment and its associated software. Results showed that the Luffa/epoxy composites has higher loss factor and dynamic modulus when the Luffa fiber is treated before the composite fabrication. The highest Young's modulus obtained was 4.05±0.31 GPa for mercerized Luffa/epoxy. For hornificated Luffa/epoxy composite the highest loss factor and shear modulus values obtained, were 0.0337±0.003 and 1.46±0.13 GPa respectively.

Oxidized Carbonized Cellulose-Coated Filters for Environmental Contaminant Adsorption and Detection

“…WAXD measurements further showed that the physical character of the filters was largely unaffected by the cationization reaction, apart from minor swelling of C75 and C150 (Figure S2). However, a small change in the crystalline character and content of the cationized filters could be observed compared to pristine cellulose (Figure S3). All filters showed crystalline planes belonging to cellulose I, which are (101), (101̅), (002), and (040) at around 14.8, 16.5, 22.6–22.9, and 34.2°, respectively .…”

Caracterização Do Compósito Epoxídico Com Tecido De Buriti Por Drx, Eds E Mev

“…Observa-se que um dos picos mais acentuados é o de Platina, porém este pico refere-se a recobrimento da amostra. Além disso, é possível observar picos característicos a Silício e Cálcio, entretanto como citado por Quinayá [10], esses picos são devidos a alguns precipitados presentes na fibra. Na Figura 5 é mostrado o difratograma obtido para o compósito com os três teores analisados 10, 20 e 30% de reforço, onde é possível observar a presença de picos apresentam os picos referentes aos planos cristalinos característicos dos materiais lignocelulósicos e halos amorfos em aproximadamente 2θ = 25º que são característicos do compósito epoxídico [11,12].…”

The real reasons for choosing bushing fiber (Luffa cylindrica): A bibliographic review

“…The results showed that the elastic modulus values are higher in luffa/epoxy composites made from fibers treated with mercerization and hornification, in which this may be related to higher crystallization values of the treated fibers and efficient removal of non-cellulosic components from the amorphous regions [30]. A previous study emphasizes that the effect of the mercerization treatment by weight of NaOH on the fibers produces only a small increase in flexural strength, and the best results were obtained with the 5% NaOH solution [1].…”