Covalent functionalization of polyhedral graphitic particles synthesized by arc discharge from graphite

Abstract

Carbon materials including carbon nanoparticles, such as nanographite, graphene and graphenic materials, and carbon nanotubes are known to be highly hydrophobic. Oxidation treatments are widely used as the best methods to improve their affinity in a liquid medium or a polymer matrix so that they can be dispersed, handled and processed. Here, we have applied eight different oxidation treatments in order to graft oxygen-containing functional groups at the surface of polyhedral graphitic particles synthesized by arc discharge from graphite, also called astralenes. The used functionalization approaches include both standard chemical attack by strong oxidants and radical functionalization of the sp network by direct C[double bond, length as m-dash]C bond opening. Commonly efficient functionalization methods were unsuccessful to functionalize astralenes while radicals generated from arylhydrazine could lead to functionalization of the outer surface of astralenes. The occurrence of functionalization could be shown by TGA coupled with MS and XPS. The reported method represents the first example of functionalization of astralenes. The efficiency of the applied functionalization methods is discussed considering the chemical reactivity of different carbon nanomaterials including graphene and carbon nanotubes.

Progress in-situ synthesis of graphitic carbon nanoparticles with physical vapour deposition

“…It is deduced that the arc method also produces clusters, agglomerations, strings, nanohorns, onions, and their hybrids. More details on graphitic particles synthesis with arc discharge can be found in the literature [39,40,121,122].…”

Non-covalent and covalent immobilization of Candida antarctica lipase B on chemically modified multiwalled carbon nanotubes for a green acylation process in supercritical CO2

“…For the selective removal of the metal-based impurities, rMWCNT was submitted to a chlorine-based treatment 20 at 1000°C for 2 h. The purified MWCNTs were named pMWCNT. They were functionalized following a liquid phase method using an alkaline solution of KMnO4 21,22 . Typically, 100 mg of the purified MWCNT powder were added to 60 mL of KMnO4 0.2 M and 60 mL of NaOH 0.2 M in a round bottom flask equipped with a condenser and refluxed for 40 min.…”