Composite materials made with polymer and carbon nanotubes (CNTs) are expected to have enhanced mechanical, thermal and electrical properties, due to extraordinary properties exhibited by carbon nanotubes themselves. However due to their insolubility in common solvents, homogeneous dispersion of CNTs in polymer matrix remains challenging. One way to overcome the problem is to functionalize their surface. In our work we used functionalization not only to modify solubility of nanotubes, but also to make covalent links between nanotubes surface and polymer by chemical reaction. Two kind of polymers have been used - thermoset (epoxy) and thermoplastic (PEEK) - and functionalization has been followed using different characterization techniques such as XRD, FT Raman, TEM, XPS and NEXAFS. Then mechanical and electrical tests have been performed.

Composite materials made with polymer and carbon nanotubes (CNTs) are expected to have enhanced mechanical, thermal and electrical properties, due to extraordinary properties exhibited by carbon nanotubes themselves. However due to their insolubility in common solvents, homogeneous dispersion of CNTs in polymer matrix remains challenging. One way to overcome the problem is to functionalize their surface. In our work we used functionalization not only to modify solubility of nanotubes, but also to make covalent links between nanotubes surface and polymer by chemical reaction. Two kind of polymers have been used – thermoset (epoxy) and thermoplastic (PEEK) – and functionalization has been followed using different characterization techniques such as XRD, FT Raman, TEM, XPS and NEXAFS. Then mechanical and electrical tests have been performed. A functionalization method has been successfully applied to functionalize carbon nanotubes surface, then to graft polymer chains like SPEEK, making a composite material with covalent bond between the nanotubes and the polymer. Grafting has been evidenced using spectroscopy techniques such as NEXAFS, XPS or FT Raman. Nevertheless shaping of the PEEK/SPEEK-MWNTs composite sample in order to make mechanical or electrical measurements remains extremely difficult and so far no satisfying method has been found. However mechanical and electrical properties have been enhanced when mixing epoxy resin with functionalized carbon nanotubes. In particular it has been shown that conductivity increases drastically when nanotubes weight fraction increases.

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

Among many extraordinary properties, 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.[1] 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.[2,3] Evidence of covalent functionalization of MWNTs by SPEEK macromolecules was given by near-edge X-ray absorption fine structure spectroscopy (NEXAFS) at the C K-edge, O K-edge, and N K-edge and X-ray photoelectron spectroscopy (XPS). Mechanical properties of the MWNT-SPEEK composite material were then tested to quantify the enhancement of Young’s modulus.

We have investigated the experimental x-ray and far-infrared responses of three polythiophenes synthesized from a thiophene, alpha-bithiophene and alpha-quaterthiophene monomer. The x-ray data show that the crystallinity of the different polythiophene samples depends on the synthesis conditions. An excellent correlation between the crystallinity of polythiophenes and their far-infrared signatures is demonstrated. In addition, the assignment of the far-infrared phonon modes in polythiophenes is given by a direct comparison with its oligomers. In particular, the ring libration inside the polymeric chain, directly involved in the electron-phonon coupling, is assigned.

A long-range ordered organic/inorganic material is synthesized from a bissilane, (EtO)3Si–(CH2)3–NHCONH–C6H4–NHCONH–(CH2)3–Si(OEt)3. This crosslinked sol–gel solid exhibits a supramolecular organization via intermolecular hydrogen bonding interactions between urea groups (–NHCONH–) and covalent siloxane bonding, Si–O–Si . Time-resolved in situ X-ray measurements (coupling small- and wide-angle X-ray scattering techniques) are performed to follow the different steps involved in the synthetic process. A new mechanism based on the crystallization of the hydrolyzed species followed by their polycondensation in solid state is proposed.