Carbon black functional group oxygen

Figure 26. XPS data in the carbon 1 s region for a UHV cleaved graphite reference (HOPG) and a carbon black sample used in the titration experiments of Fig. 25. The arrow marks the position of the graphite surface plasmon. The top section of the modified spectrum in the high-binding energy side reveals several weak peaks for oxygen functional groups after removal of the asymmetric line profile from the main peak.

Most carbon blacks have a low affinity for water, i.e. they are hydrophobic. However, the level of hydrophobicity is reduced by the presence of chemisorbed oxygen and certain functional groups (Walker and Janov) 1968 Bradley et al., 1995). The relative extents of the polar and hydrophobic areas of carton blacks have been studied by various methods (Boehm, 1994), including energy of immersion measurements (Barton and Harrison, 1975) and by liquid flow calorimetry (Groszek,... 

The oldest method for the modification of carbon black surface chemistry is oxidation. Common oxidants include air, hydrogen peroxide, hypochlorites, nitric acid, nitrogen dioxide, ozone and persulfates. Each reagent produces a mixture of oxygen functional groups on the surface, with the distribution depending on the oxidant. Materials that disperse in water can be produced with sufficient oxidation, and hypochlorites and persulfates have been used to make water dispersible carbon blacks for inkjet inks. 

Oxygen-containing functional groups on the carbon black surface can also be created through specific oxidative aftertreatment. Oxygen content levels of 15% and higher are possible. 

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