Carbon black surface oxides

Chem. Descrip. Eumace carbon black, surface oxidized (treated) grade CAS 1333-86-4 EINECS/ELINCS 215-609-9 Uses Colorant, filler for high qualify heat-set inks, sheet fed/ofbet inks, med. color coatings Features Med. color... 

Chem. Descrip. Furnace carbon black, surface oxidized (treated) grade... 

Extractable matter should be removed by extraction with organic solvents, e.g., xylene. This is especially important for carbon blacks (25), Oxidized carbon may contain small amounts of oxalic acid. King (33, 34) found 0.002 meq/gm of oxalic acid in oxygen-treated sugar charcoal. More severe is the contamination of the surface with adsorbed gases, mainly carbon dioxide and water. Activated carbon with narrow pores may contain considerable amounts of carbon dioxide (28). The best... 

Similar waves in the cathodic polarogram were observed by Donnet and Henrich 58) using oxidized carbon black. The wave disappeared after treatment with isobutyronitrile. It was assumed that isobutyro-nitrile gives an addition reaction with quinones. No reaction with this reagent was observed after reduction with hydrogen iodide, after treatment with aniline, or after treatment with diazomethane. The latter finding confirms the assumption by Studebaker et al. 38) that diazomethane is added to the quinones in the carbon black surface. 

It appears from the evolution of the adhesion index that a distinction has to be made between the interactions carbon blacks are able to have with unsaturated or with saturated (or near-to-saturated) elastomers. Thus, the adhesion index of butyl rubber is enhanced upon oxidation of the black, while the reverse is observed with polybutadiene 38). The improvement of the reinforcing ability of carbon black upon oxidation, in the former case, has been interpreted by Gessler 401 as due to chemical interactions of butyl rubber with active functional groups on the solid surface. Gessler, relating the reinforcing characteristics of the oxidized carbon black for butyl rubber to the presence of carboxyl groups on the surface of the filler, postulated a cationic... 

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. 

Rubber tyres are by far the most visible of rubber products. Identification is trivial and collection is well organized. Recycling and disposal, however, are less evident. A major route for tyres is their use as a supplemental fuel in cement kilns. Major compounds in tyres are styrene-butadiene rubber (SBR), synthetic and natural polyisoprene rubber, steel cord, carbon black, zinc oxide, sulphur and vulcanization-controlling chemicals. Tyres can be retreaded, which is economic for large sizes (truck tyres), or ground to crumb or powder (cryogenic grinding). Such materials have some limited market potential as an additive in asphalt, and in surfaces for tennis courts or athletics. 

Because carbon black is the preferred support material for electrocatalysts, the methods of preparation of (bi)metallic nanoparticles are somewhat more restricted than with the oxide supports widely used in gas-phase heterogeneous catalysis. A further requirement imposed by the reduced mass-transport rates of the reactant molecules in the liquid phase versus the gas phase is that the metal loadings on the carbon support must be very high, e.g., at least lOwt.% versus 0.1-1 wt.% typically used in gas-phase catalysts. The relatively inert character of the carbon black surface plus the high metal loading means that widely practiced methods such as ion exchange [9] are not effective. The preferred methods are based on preparation of colloidal precursors, which are adsorbed onto the carbon black surface and then thermally decomposed or hydrogen-reduced to the (bi)metallic state. This method was pioneered by Petrow and Allen [10], and in the period from about 1970-1995 various colloidal methods are described essentially only in the patent literature. A useful survey of methods described in this literature can be found in the review by Stonehart [11]. Since about 1995, there has been more disclosure of colloidal methods in research journals, such as the papers by Boennemann and co-workers [12]. 

Chemical heterogeneity of a surface is an important property affecting adhesion, adsorption, wettability, biocompatibility, printability and lubrication behavior of a surface. It seriously affects gas and liquid adsorption capacity of a substrate and also the extent of a catalysis reaction. As an example, the partial oxidation of carbon black surfaces has an important, influence on their adsorptive behavior. In a chemically heterogeneous catalyst, the composition and the chemical (valence) state of the surface atoms or molecules are very important, and such a catalyst may only have the power to catalyze a specific chemical reaction if the heterogeneity of its surface structure can be controlled and reproduced during the synthesis. Thus in many instances, it is necessary to determine the chemical... 

Kinoshita and co-workers studied the presence of redox couples after modification of carbon black surfaces [190]. Cyclic voltammograms of carbon blacks after heating at high temperatures and oxidation treatments showed clear evidence of the presence of redox couples on the carbon black surface. After heat treatment, the voltammogram of the carbon black surface showed no evidence for oxidation or reduction peaks. However, after oxidation, an increase in both the anodic and cathodic currents was observed (Fig. 9). 

The same results were reported by Bradley and co-workers [303], who correlated the enthalpy of immersion in water for a series of oxidized nan-porous carbon blacks with the total surface oxygen level measured by XPS. Nevertheless, when the carbon blacks were oxidized with nitric acid, the heat of immersion did not show the same trend. The data showed... 

This observation allows us to believe that acidic groups on carbon blacks are mainly produced by surface oxidation in the production process, probably during drying following pelletization. Therefore, acidic groups could be considered an alteration of carbon black surface. 

Plasma treatment is one of the most popular treatments of carbon materials. This treatment takes place only on the carbon black surfaces without changing its bulk properties. Besides, it was possible to process under oxidative, reductive, or inactive, atmospheres [79]. Therefore, in this work, the effects of the plasma treatment for CBs on the modification of surface functional groups and the deposition of Pt catalyst were investigated. 

Aggregate gassification. After its formation and growth, the carbon black surface undergoes reaction with the gas phase, resulting in an etched surface. Species such as CO2, H2O, and of course any residual oxygen attack the carbon surface. The oxidation is determined by gas-phase conditions, such as temperature, oxidant concentration, and flow rates. 

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