Reinforcement of Rubbers with Short Aramid Fibers

Among short fiber reinforced composites, those with rubbery matrices have gained great importance due to the advantages they have in processing and low cost, coupled with high strength. These composites combine the elastic behavior of rubbers with strength and stiffness of fibers. Reinforcement with short fibers offers some attractive features such as design flexibility, high modulus, tear strength, etc. The degree of reinforcement depends upon many parameters such as: the nature of the rubber matrix, the type of fiber, the concentration and orientation of fibers, fiber to rubber adhesion (generation of a strong interface), fiber length and aspect ratio of the fibers.
       In this research aramid fibers have been chosen because of their significantly higher modulus and strength, compared to other commercial fibers. Compounds based on different types of rubbers have been made to investigate the usage of these fibers in different applications. Short aramid fibers have been supplied by Teijin Aramid BV, with different kinds of surface treatments which result in different rubber-fiber interfaces. The reinforcing effect of these short aramid fibers has been studied by mechanical and viscoelastic experiments, and by studying the fracture surfaces with microscopy techniques.