The possibility of the use of PANOX and aramid fibers, both as reinforcement material in the formulation of composites for the production of frictional material for automotive brakes in substitution to the asbestos, is studied in this paper. Several compositions were formulated with different concentrations and the properties obtained were analysed. The properties of the fibers and of the composites, as well as the mechanical performance of the pad brake, was evaluated by using the friction coefficient obtained by Krauss's method. The results are compared with other standard material available in the market. Both fibers can be a good alternative instead asbestos in the production of friction material, to let the PANOX fibers to become in a final product with technological and industrial interest.1026368Determinação da Densidade Relativa para Guarnições de Embreagem e do Freio, , Rio de Janeiro NBR-5544Determinação de Dureza Gogan de Materials de Frição para Guamições de Embreagem doFreios, , Rio de Janeiro NBR-5520Determinação da Resistência ao Cisalhamento de Materiais de Fricção, , Rio de Janeiro NBR-5537Pastilhas de freio a disco Determinação do Atrito e Desgaste Através da Bancada de Ensaios Krauss, , Rio de Janeiro NBR-6143Del Arco, A.P., (1997) Análise e desenvolvimento do processo de obtenção de fibras de carbono a partir de estabilização oxidativa das fibras de poliacrilonitrila, , Tese de Doutorade, Faculdade de Engenharia Química, Universidade Estadual de CampinasMatthews, F.L., Rawlings, R.D., (1996) Composite Materials: Engineering and SciencePilato, L.A., Knop, A., (1985) Phenolic Resins. Chemestry, Aplications and PerformancesPreston, J., Aramid fibers (1986) Encyclopedia of Polymer Science and Engineering, 2 ed., 2, p. 97Seiler, H.G., (1988) Handbook on the Toxicity of Inorganic CompoundsStrong, A.B., (1989) Fundamental of Composites Manufacturing: Materials, Methods, and Applications