Ballistic behavior of a hybrid composite reinforced with curaua and aramid fabric subjected to ultraviolet radiation

Mobile ballistic armors, particularly those intended for personal protection, are also designed with lowest possible weight. Composite materials are the best choice for this kind of application, especially laminated composites reinforced with high-performance fibers or fabrics. Owing to environmental problems, research works on hybrid composites based on natural instead of synthetics fibers is already a promising line of investigation. These composites, when used outdoors, are exposed to ultraviolet (UV) radiation and some properties and applied behavior may change. Therefore, this work investigated the ballistic behavior of a thermoset polyester resin laminated hybrid composite reinforced with a natural fiber mat and aramid fabric after exposure to UV radiation. The mat was produced with curaua fiber, one of the strongest natural fibers. Infrared spectroscopy analysis and determination of the degree of cross-linking, to identify possible structural changes in the curaua mat, are performed after two different exposure times to UV radiation The mechanism of failure related to the ballistic impact is analyzed by visual inspection. The results show that the composite is influenced by UV radiation, which affects the ballistic performance due to delamination on the interface of plies as well as chain scission on curaua fibers and increasing crosslinking of the polyester resin. The delamination was attributed to a low interfacial energy between the polyester matrix and curaua fibers. (C) 2018 Brazilian Metallurgical, Materials and Mining Association. Published by Elsevier Editora Ltda. This is an open access article under the CC BY-NC-ND license (http://creativecommons/org/licenses/by-nc-nd/4.0/)