Thiol functionalities were grafted at the surface of carbon fibers in order to improve the adhesion strength with an acrylate matrix photo-cured by ultraviolet light via a thiol-ene reaction. As revealed by X-ray photoelectron spectroscopy, the grafting was achieved by a reaction between propylene sulfide and thehydroxyl groups located at the surface of the fiber, with the presence of triethylamine. A significant improvement of the interfacial shear strength, measured by a micromechanical test derived from the pull-out test, was obtained (+ 18%). Generating covalent bonding between the carbon fiber surface and a thermoset polymerizing through a radical mechanism by grafting a chain transfer agent seemed to be an efficient way to improve adhesion strength at the interface. (C) 2013 Elsevier B. V. All rights reserved.