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Dispersion of carbon nanotubes in polymers: from nanostructuration to high performances composites
Thomas Périé, doctorant Crédits : ESPCI ParisTechWe have synthesized nanostructured composites of carbon nanotubes (CNT) in two different ways.
The first method relies on the dispersion in a matrix of a masterbatch containing polymers and high loading of CNT. The masterbatch contents were optimized on the one hand to help the CNT dispersion and on the other hand to modify the properties of the matrix by structuring it. A masterbatch of poly(styrene-b-butadiene-b-methyl methacrylate) and CNT was re-dispersed in a fluoride polymer and yielded a stiff and ductile composite. We also used a reactive masterbatch with polyamide-6 (PA6) and CNT. The co-continuous morphology achieved after adding maleized polyethylene resulted in composites that combine stiffness, ductility, solvent resistance and electrical conductivity.
The second method allowed us to demonstrate a specific interaction between PA6 and CNT inside nanostructured PE*/PA6 matrices. The PA6 adsorbs on the CNT resulting (above a percolation threshold) in a composite showing a microstructure of a soldered CNT network brazed by PA6. This brazed network yields composites with unique high temperature creep resistance.
Surprisingly, we showed that after extracting the PE* matrix, the soldered network behaves like a gel. These new kinds of gels can be reversibly swollen by the addition of different solvents and possess dynamic electrical properties which depend on their swelling ratio.