24th ABCM International Congress of Mechanical Engineering December 3-8, 2017, Curitiba, PR, Brazil COBEM-2017-0501 MECHANICAL BEHAVIOR OF COMPOSITE OF POLYURETHANE REINFORCED WITH COTTON FIBER AND ALUMINA TRIHYDRATE Amanda Albertin Xavier da Silva Enio Henrique Pires da Silva Danilo Biazon Janes Sandra Mara Domiciano Romeu Rony Cavalcante da Costa Federal University of Technology - Parana – Department of Mechanical Engineering, Cornélio Procópio, PR, Brazil amandaaxavier@hotmail.com, enio.piresdasilva@outlook.com, danilobiazon96@gmail.com, domiciano@utfpr.edu.be, romeu@utfpr.edu.br Abstract. This work aims to evaluate the mechanical behavior of the composite of polyurethane (PU) derived from a blend of vegetable oils with reinforcement of cotton fiber (CF) fabrics and added Alumina Trihydrate (ATH). For comparison and study, tests were performed for characterization of the pure PU, PU doped with different ATH contents (10%, 20% and 30%), of PU composite reinforced with cotton fiber and the PU composite reinforced with cotton fiber and ATH. The fibers were oriented at 0 °, ± 45 ° and 90 °. The mechanical properties obtained according to the tensile test for the laminated PU composite reinforced with cotton fiber and doped with 30% of ATH presented an elasticity modulus of 4.733 GPa and ultimate tensile strength of approximately 60 MPa for the samples oriented at 0°. The pure PU exhibited an elasticity modulus of 1.703 GPa and ultimate tensile strength of 39.715 MPa. When comparing the composite results with the pure polyurethane matrix, a significant stiffness and mechanical resistance enhancement was obtained. Keywords: Composite, Polyurethane, Cotton fibers, Alumina trihydrate, Characterization. 1. INTRODUCTION The use of raw materials from renewable sources for research involving the use of green polymers as substitutes for petroleum-based polymers and for the manufacture of bio-composites showed a great growth (Quirino, et al., 2015; Milanese, Cioffi and Voorwald, 2012). The main reason of those researches is to decrease the risk of environmental damages caused by petro-based polymers and synthetic fibers (Machado, et al., 2010; Sanjay, Arpitha and Yogesha, 2015, Alomayri, Shaikh and Low, 2014) Among the numerous types of composites, there is a clear emphasis on polymer composites reinforced with fibers. The natural fibers are given special attention because they present: low cost, low density, good mechanical strength and also because they are derived from renewable raw materials. In recent years, attempts have been made to reduce the use of synthetic fibers and still considerably reduce the weight of the structures, taking advantage of the lower density and cost that some natural fibers provide. In this sense, natural fibers were widely used as reinforcement in composites of interior parts of commercial vehicles (Koronis; Silva; Fontul; 2013; Holbery and Hoston, 2006). In order to utilize polymeric composites reinforced with natural fibers in vehicle interiors, they must present certain safety precautions when exposed to fire situations, giving enough time to the rescue of the victims. Thus, researches involving the use of flame retardant additives in polymeric materials and polymeric composites have been necessary to allow the use of these materials according to existent standards. Therefore, the main goal of this paper is the mechanical characterization of a bio-composite of polyurethane (PU) derived from a blend of vegetable oils reinforced with cotton fiber (CF) and doped with alumina trihydrate (ATH), according to the tensile test.