Élaboration et étude des performances mécaniques des composites à matrice polymère

Abstract

Since the appearance of the first resin parts reinforced with synthetic fibers, such as Kevlar fibers, carbon fibers or glass fibers, the use of composite materials in industrial applications has increased for several years (1940) in all industries: automotive, aeronautics, space, marine, construction, medical, etc. On the other hand, composites reinforced with natural fibers have attracted more and more attention due to their low cost, their biodegradability and their availability. The main objective of this work is to develop a new hybrid bio-composite reinforced with natural/natural fibers. The percentages of fibers are obtained by on statistical optimization of the mechanical properties of bio-composites reinforced with the individual fiber composites in the tensile and bending tests. In order to define the optimal material, the following steps were taken: - Firstly, the mechanical properties (tensile and bending) and chemical (TGA, DRX and MEB) of the materials used (resins: polyester and epoxy; fibers: sisal, flax and jute) was carried out. - Secondly, the bio-composites (sisal/polyester, flax/polyester, jute/polyester, sisal/epoxy, flax/epoxy and jute/epoxy) are developed according to the Box-Behnken experimental design and tested in tensile and bending. From these, a modeling and optimization are opted in order to maximize the tensile and flexural mechanical properties in tensile and bending tests. In addition, confirmation of the optimization results was achieved through the development of the new hybrid combinations. - The best tensile results were recorded for a combination of jute fibers and flax fibers (14.4% and 5.6%), treated with bicarbonate for approximately 4 hours. whereas, the best mechanical performance in bending correspond to a reinforcement of 17.4% of jute fiber and 2.6% of sisal fiber, treated with bicarbonate for 5 h 55. - Finally, the effects of input variables such as type of fibers, types of chemical treatment, volume fraction and treatment duration of fiber on the mechanical properties of composite materials were investigated.