Résumé
Among many extraordinary properties, Carbon nanotubes (CNTs) have a very high Young modulus, generally reported with a value of ~ 1 TPa, making this kind of material even stronger than diamond and carbon fiber. Moreover their very light weight makes them first choice materials for mechanical reinforcement of polymer matrices. Most of previous studies using CNTs deal with so-called physical mixing, meaning that there is no strong link between polymer and nanotube surface, resulting in a relatively poor enhancement of the composite Young's modulus. In our study, we first investigated the functionalization of multi-walled carbon nanotubes (MWNTs) surface by sulfonated poly (ether ether ketone) (SPEEK) chains using a direct attachment reaction, PEEK being known as a very promising polymer especially in aerospace field for its particularly high glass transition and melting temperature, compared with most of polymer material. MWNTs were oxidized by a nitric acid treatment to generate carboxyl groups on their surface, which then react with sulfonated groups of SPEEK using hexane diamine as an interlinking molecule. Characterization of covalent functionalization of MWNTs by SPEEK macromolecules was obtained by electron microscopy, infra-red spectroscopy and near-edge X-ray absorption fine structure spectroscopy (NEXAFS) at O K-edge. Mechanical properties of the MWNT-SPEEK composite material have to be tested to quantify the enhancement of Young's modulus