Mechanical properties of epoxies reinforced with chloride-treated aramid fibers

Abstract

Surface treatment of aramid fibers by immersion in a solution of methacryloyl chloride in carbon tetrachloride was carried out, and the resulting material was examined by means of electron microscopy and chemical analysis in an attempt to record any changes in the morphology and nature of the surface. Mechanical testing of tensile, flexural, and interlaminar shear strength, as well as dynamic mechanical analysis (DMA), were performed in an attempt to explore the effect of this treatment on the strength of the fiber. In a subsequent stage, the performance of those fibers as reinforcement in composites of epoxy matrix was assessed. The aim of this study was to provide more information about the interactions between the chloride-treated aramid fibers and the epoxy resin and, more specifically, to compare the behavior of the epoxy matrix composites with those composed of unsaturated polyester, polyethylene, and polyurethane matrix, which were studied in the past. It was found that specimens containing chloride-treated aramids display better flexural properties, whereas their tensile strength is drastically reduced. Improved performance was also identified by the DMA experiments.

Flexural and Shear Properties of Silica Particle Modified Glass Fiber Reinforced Epoxy Composite

“…A similar theory was discussed on the effect of fiber surface chemical treatment on the properties of the composite [28][29][30][31][32][33][34][35][36]. A major use of this treatment is to roughen the surface of the fiber so that the fiber-matrix interlocking effect can happen.…”

“…Boynard et al [32] treated the sponge gourd fibers with NaOH solution to remove the smooth outer surface of the sponge fiber and in doing so, improved the flexural properties of the composite. Tarantili and Andreopoulos [28] treated the surface of aramid fibers by immersing them in a solution of methacryloyl chloride in carbon tetrachloride before the fibers were used in aramidÀepoxy composite. The boundary interlocking on the resulting small defects was discussed and the improvement of flexural and interlaminar shear strengths was noted in the results.…”

“…When these modified GFs are applied in the epoxy matrix, the 'rough' surface of the GF makes the mechanical interlocking between the GF and the epoxy matrix much more pronounced. As studied by other researchers [27,28,31,32,37,38], this mechanical interlocking at the fiber-matrix interface helps to enhance the fiberÀmatrix bond and improves the flexural and shear properties of the composites. Greater work must be done to deform or shear the samples when the fiberÀmatrix bond is improved in this manner.…”

Surface Modification of Aramid Fibers by Bio-Inspired Poly(dopamine) and Epoxy Functionalized Silane Grafting

“…These studies and techniques mainly focused on chemical etching and grafting, [3][4][5][6][7][8][9] plasma treatment, [10][11][12] ultrasonic treatment, 13 γ-ray irradiation, 14 and ultraviolet radiation. 15 The chemical etching or grafting generally modify the surface by introducing active functional groups like amino, hydroxyl, and carbonyl through etching, nitrification, reduction, or chlorosulfonation.…”

“…4 In Wu's research, Kevlar 49 fibers were surface-modified by NH 3 -, O 2 -, and H 2 O-plasma etching and chlorosulfonation and subsequent reaction with some reagents (glycine, deionized water, ethylendeiamine, and 1-butanol) to improve the adhesion to epoxy resin. 10 However, these approaches were limited in practical industrial use due to multistep procedures, high cost instruments, stringent reaction conditions, toxic materials and decrease of fiber strength and so on.…”