Preparation and Properties of Polymer-grafted Carbon Nanotubes and Nanofibers

Abstract

Recent advances in surface grafting of polymers onto carbon nanotubes (CNT) and nanofibers, such as vapor grown carbon fiber (VGCF), are reviewed. The grafting of polymers onto these surfaces was achieved by (1) the “grafting onto” method, (2) “polymer reaction” method, (3) “grafting from” method, and (4) “stepwise growth” method by dendrimer synthesis methodology. For the grafting of polymers, surface functional groups, such as carboxyl and phenolic hydroxyl groups, previously introduced onto the surface by oxidation with nitric acid, were used as grafting sites. These functional groups were converted into various initiating groups and surface initiated graft polymerization was achieved. The graphene sheet (polycondensed aromatic rings) of CNT and VGCF were used as grafting sites by using ligand-exchange reaction with polymers containing ferrocene moieties. The radical trapping nature of CNT and VGCF surface was used for the grafting of polymers. Dispersibility in solvents for good solvents of grafted polymer was remarkably improved by the surface grafting of polymers onto CNT and VGCF surfaces. The response of electric resistance of the composite prepared from polymer-grafted CNT and VGCF to solvent vapor and temperature is discussed.