Abstract
We investigated the effect of modified aluminosilicates, including bentonite from Armenia (BA) modified with quaternary ammonium salts (BAQAS) and phosphonium salts (BAQPS), on the mechanical properties and morphology of Kevlar/epoxy composites. The Kevlar/epoxy composites containing 1.0 or 3.0 wt.% modified bentonites were fabricated using the hand lay-up technique. The mechanical properties, including the tensile, flexural, and in-plane shear strength, were tested. Based on the obtained results, we found that the mechanical properties increased with modified bentonite loading. The best results were obtained for composites containing 3 wt.% BAQAS, as most of the mechanical properties were significantly improved (tensile strength 302.9 MPa (+30%), Young’s modulus 16.3 GPa (+17%), flexural modulus 23.4 GPa (+12.5%), in-plane shear strength 22.8 MPa (+24.5%), and in-plane shear modulus 677.2 MPa (+42%)). The obtained improvements in the mechanical properties are attributed to the uniform dispersion of the filler, which was confirmed by the highest increase in the intergallery spacing, from 28.3 Å for BAQAS to 45.1 Å for the composite with 3 wt.% BAQAS. Scanning electron microscopy (SEM) analysis of the brittle fracture surface indicated that the addition of modified bentonite to the epoxy matrix changed the morphology of the Kevlar/epoxy/organoclay composites and improved the fiber–matrix interfacial adhesion.
Highlights
Among the composites with a polymer matrix, fiber reinforced composites have been widely used in the construction industry, and their applications are increasing
The arithmetic means from ten tests of tensile strength for each fabric-The results, results, i.e., i.e.,the the arithmetic means from ten tests of tensile strength foraramid each aramid reinforced epoxy composites with modified bentonites are collected in
The bentonites were modified with quaternary ammonium and phosphonium salts
Summary
Among the composites with a polymer matrix, fiber reinforced composites have been widely used in the construction industry, and their applications are increasing. A continuous fiber polymer matrix composite offers high strength to weight, high toughness to weight, and design flexibility to match the material with the structural demands. Kevlar fiber reinforced composites (KFCs) have been widely used as impact-resistant structures, such as in anti-ballistic applications, due to their high degree of toughness, associated with the failure mechanism, damage tolerance, and good impact performance [1,2,3,4]. Despite the excellent properties of KFCs, there are some disadvantages, such as low stiffness and compression strength, limiting their application in the aviation industry, shipbuilding, or sport goods. To increase the application capabilities of KFCs, many studies have investigated methods for improving the damage tolerance properties of aramid fiber/polymer composites. Chemical grafting exhibits promising potential [5,6,7,8,9]
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