Carbon nanotubes (CNT) possess excellent intrinsic characteristics such as exceptionally high mechanical and conductive properties which make them the prime candidate to reinforce high-performance composite structures. However, location and dispersion state of the CNTs are of particular importance to achieve the mechanical and electrical enhancement of carbon-reinforced composites. In the frame of European Project SARISTU, different approaches were investigated by the different partners (e.g., veils, powdered doped prepreg, and doped adhesives). Each approaches required specific dispersion solution. Along its existence, Nanocyl has developed a large experience in incorporation of CNTs in different resins (thermoplastics, thermosets, etc.) using improved innovative mixing process, CNT surface modification (functionalization) or by adding some dispersing agents or compatibilizers. Applying this expertise to SARISTU context, the requested products were delivered in the suitable form for each scenario. As an example, ground CNT/thermoplastics compounds were produced for powdered doped prepreg and different grades of doped thermoplastics for veils production.

En este trabajo se presenta un estudio de la cristalizacion isotermica del sistema policaprolactona/nanotubos de carbon de pared multiple, con contenidos de nanotubos que varian entre 0 y 5%. Se realizaron ensayos de Calorimetria Diferencial de Barrido (DSC) que ajustan de manera satisfactoria a la teoria cinetica de cristalizacion de Lauritzen y Hoffman This paper presents an isothermal crystallization study of polycaprolactone/multi-wall carbon nanotube system with nanotube contents ranging between 0 and 5%. Tests were performed by differential scanning calorimetry (DSC). The results can be satisfactorily fitted to the kinetic theory of crystallization of Lauritzen and Hoffman.

Since their discovery at the beginning of the 1990s, carbon nanotubes (CNTs) have been the focus of considerable research by both academia and industry due to their remarkable and unique electronic and mechanical properties. Among numerous potential applications of CNTs, their use as reinforcing materials for polymers has recently received considerable attention since their exceptional mechanical properties, combined with their low density, offer tremendous opportunities for the development of fundamentally new material systems. However, the key challenge remains to reach a high level of nanoparticle dissociation (i.e. to break down the cohesion of aggregated CNTs) as well as a fine dispersion upon melt blending within the selected matrices. Therefore, this contribution aims at reviewing the exceptional efficiency of CNT coating by a thin layer of polymer as obtained by an in situ polymerization process catalysed directly from the nanofiller surface, known as the 'polymerization-filling technique'. This process allows for complete destructuring of the native filler aggregates. Interestingly enough, such surface-coated carbon nanotubes can be added as 'masterbatch' in commercial polymeric matrices leading to the production of polymer nanocomposites displaying much better thermomechanical, flame retardant and electrical conductive properties even at very low filler loading. (c) 2007 Society of Chemical Industry.

Multiwalled carbon nanotubes (MWNT) are introduced into thermoplastic matrices (polycarbonate and polyamide) by melt blending using polyethylene (PE) based concentrates with high MWNT loadings (24-44 wt.-%). MWNT surfaces were treated with a metallocene-based complex to afford the in-situ polymerization of ethylene directly from the surface. The resulting concentrates showed excellent MWNT pre-dispersion. Due to the high interfacial energy between MWNT and PE, the nanotubes migrate into matrix polymers with lower interfacial energies, like polycarbonate and polyamide, and thereby remain in their. excellent dispersion state. Thus, electrical percolation is achieved at lower MWNT contents as compared to direct incorporation. For polycarbonate it is shifted from 0.75 to 0.25 wt.-%.

Homogeneous or periodical surface coating of multiwalled carbon nanotubes (MWNTs) can be achieved by in situ polymerization of ethylene as catalyzed directly from the nanotube surface- treated by a highly active metallocene-based complex, e.g., Cp*2ZrCl2/methylaluminoxane. This polyethylene (PE) coating allows for the break-up of the native nanotube bundles. Immobilization of methylaluminoxane onto the surface of the carbon nanotubes was evidenced by scanning electron microscopy (SEM) and confirmed by X-ray photoelectron microscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). The thermal behaviour and degradation were studied by means of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Transmission electron microscopy (TEM) was used to image polymer-coated MWNTs, showing either a relatively smooth or a textured polymer coating present on the surface of individual, debundled nanotubes, i.e., PE/MWNT nanohybrid “sausage”-like or “shish-kebab”-like structures, respectively. It was clearly demonstrated that by modifying the design of the catalytic complexes, it was possible to tune by a reproducible way the morphology of the PE coating around the MWNTs.

Nanocomposite comprenant une dispersion de nanotubes de carbone au sein d'une matrice polymerique, dans lequel ladite matrice polymerique comporte une polyolefine polymerisee in situ sur lesdits nanotubes de carbone ladite polyolefine formant un enrobage autour dudit nanotube de carbone.

HDPE composites. For each case, a deep modification of the properties of the obtained composites has been observed when compared to other preparative techniques such as melt blending, as a direct result of the very good filler dispersion and the increase in HDPE/filler adhesion. This technique has therefore been applied in the preparation of nanocomposites based on the dispersion of multi-walled carbon nanotubes in polyethylene matrices.