Polymeric fullerene oxide (fullerene ozopolymers) produced by prolonged ozonation of C60 and C70 fullerenes Original Research Article

The prolonged ozonation of C60 and C70 fullerene produces light brown to brown amorphous solids which are insoluble in chlorinated and hydrocarbon solvents but which are readily soluble in water, acetone and ethanol where they give dark-brown solutions. The polymeric and polyelectrolytic nature of these solids has been shown by viscosimetric and cryoscopic measurements. Due to the polymeric nature the solids have been called ‘ozopolymers’. The reactivity and the ozone uptake have been measured quantitatively during the ozonation of C60 and C70 fullerene in CCl4. Three different C60 ozopolymer samples have been produced at different degrees of ozonation: at O3/C60 molar ratio of 8, 14 and 26. The C70 ozopolymer has been produced at an O3/C70 molar ratio of 30. All the samples have been studied by FT-IR spectroscopy and the C60 ozopolymers have been easily reduced by the action of Zn dust and acetic acid or by the action of H2S and studied by FT-IR. The action of oxidizing agents has been studied as well. C60 ozopolymer is a polyelectrolyte rich in carboxyl groups and for this reason it possesses a high metal binding capacity similar to that of humic acids. The thermal stability of C60 ozopolymer and its reduced derivatives as well as the thermal stability of C70 ozopolymer has been checked by thermogravimetric analysis in nitrogen and air flow. Finally, the electrical conductivity of C60 ozopolymer was found to be σ=2.8×10−8 S/cm which is three orders of magnitude lower than that of pure C60.