work directed towards improving the toughness of carbon epoxy composites by carrying out laminated treatments is presented. the great variety of laminated molecules capable of being grafted onto the surface of the fiber is exploited. the combination of high tensile strength xau courtaulds fibers and narmco 5208 resin was used and enabled the effectiveness of the subsequent surface treatments to be assessed. the operating conditions for the described electrochemical treatments were determined from fragments of yarn immersed in a voltametric cell. x-ray photoelectron and secondary ion mass spectroscopy surface analyses were used to specify the nature of the grafted groups and their distribution. pull out tests were used to characterize the fiber matrix adhesion. the grafting mechanism of ethylenediamine was investigated. mechanical properties of fabricated composites having fibers with different laminated molecules were compared by using measurements of the mode 1 crack propagation energy and of interlaminar shear strength