Fluorination carbon black

Although we made no attempt to elucidate the mechanism of friction decreases in rubbers after surface fluorination, it seems to us that apart from the substitution of H atoms to F in the polymer macromolecule, which forms a fluoropolymer on the surface, there is another phenomenon that makes a significant contribution to the friction decreases, i.e., fluorination of carbon black, which is used in rubber recipes for reinforcement. It appears that when the carbon black in the surface of the rubber is fluorinated it produces a lubricating effect, followed by blooming on the surface of the treated rubber while it is under a friction load. So, in our opinion, two effects contribute to friction decrease of carbon-filled rubbers fluorination of the rubber macromolecules and fluorination of the carbon black rubbers that do not contain carbon black show a much smaller decrease in friction after XeF2 treatment. 

Fluorinated carbon, CFX, where x is between 0 and 1.3, is prepared by the direct fluorination of carbon at high temperatures [108]. Many varieties of fluorinated carbon can be prepared depending on the type of carbon used in the process (e.g. graphite, petroleum coke, carbon black, etc.) and the level of fluorination (i. e. the value of ). Fluorinated carbons, such as those manufactured by Allied-Signal (Accufluor ), Central Glass Co. (Cefbon ) and Daikin, are used for the fabrication of cathodes in lithium anode batteries and as solid lubricants [109]. 

Product with lower carbon/fluorine ratios, CF0 4 0 8, was obtained by reducing the fluorination period, while synthesis of CF0 2 0 33 was carried out at room temperature. Graphite fj 1 is the easiest material to fluorinate while carbon black ff 1 is difficult to fluorinate.12... 

X-ray diffraction patterns for different carbon/fluorine ratios demonstrate that the diffractions due to the starting materials disappear and are replaced by new diffractions.12 As shown in Table 2,12 the interlayer spacing of graphite and carbon black increases from 3.37 to 6.06 and 6.7 A. This increase is due to the electrostatic repulsion resulting from the fluorine atoms which have formed a layer above and below the carbon atoms. 

PEF treatment of carbon blacks. Due to their important specific surface areas, that range from a few m2/g to several thousands m2/g, carbon blacks react thoroughly in PEF conditions. The reactivity of various types of carbon blacks with F2-gas and other fluorinated reagents has been recently investigated by G. Nanse et al. [101-103],... 

We have chosen to present below the results obtained on furnace carbon black N115, because of its intermediate surface area of 145 m2 g-1. The fitted high resolution XPS spectra of Cls and FIs components are given in Fig. 23. Due to the complexity of the morphology of carbon blacks, ten components were required, in order to take into account the envelope of the Cls spectra. Details of the fitting procedure can be found in [101], The different assignments for C and F atoms involved in each component are shown in Table 7. For Cls envelope, there are two major peaks. The peak at lower BE, located at 284.3eV, can be assigned to the component Cls (1) which corresponds to non-functionalised sp2 and sp3 C atoms that are not affected by fluorination. The area of component (1), which is noted... 

Fig. 23. Fitted high resolution Cis and F]s XPS spectra of plasma-fluorinated furnace carbon black (Nil 5).

As a concluding remark, it is possible to modify the nature of the fluorinated film which is formed on the surface of the carbon black by acting either on the nature of the host material or on the characteristics of the plasma. Concerning the physical properties, it can be expected that the formation of a fluorinated insulating layer on the surface of the carbon blacks increases the repulsion effect between the particles. The electrical contacts between the aggregates become therefore limited and the electrical permittivity, which primarily depends on the number of particles, should be increased. 

Any kind of carbon, such as natural graphite, petroleum coke, carbon black, carbon fiber, exfoliated graphite, natural or synthetic graphite and fullerenes can be fluorinated under controlled conditions. Each carbon has unique crystalline properties. To achieve a desired degree of fluorination — or carbon fluorine ratio — numerous experiments are conducted in specialized TGFA reactors to determine the operating conditions such as fluorination temperature, fluorine flow rate, and fluorination duration. 

Each electronegative element X polarizes the C-X bond, resulting in a shift towards higher energies compared to the C peak of the graphitic carbon [143, 146,261]. The results of XPS measurements have indicated the presence of C-F and C-F2 bonds on the carbon surfaces after fluorine incorporation, and the incorporation of chlorine (both dichlorinated and monochlorinated bonds) to the carbon blacks surfaces upon chlorination [143, 146, 262], These trends have been corroborated with other techniques such as infi ared or Raman spectroscopy. 

TFE/HFP. See Fluorinated ethylene/propylene TGA 2. See Diethylene glycol diacrylate TGIC. SeeTriglycidyl isocyanurate TGM3. See PEG-3 dimethacrylate Thalo green No. 1. See Phthalocyanine green THAN. SeeTris (hydroxymethyl) aminomethane THBP. See Benzophenone-2 Thenard s blue. See Cobalt aluminum oxide Thermal acetylene black Thermal atomic black Thermal black. See Carbon black... 

The active substance of the positive electrode is the polymer of fluorinated carbon with the overall formula of (CFj ) . As a rule, subscript x in this formula is close to unity, polymerization degree n exceeds 1(X)0. The polymer of fluorinated carbon is a layered compound obtained by fluorination of carbon (graphitized or nongraphitized) in the form of a powder, fibers, or even fabrics by elementary fluorine at the temperatures of 350 - 600°C. As polyfluorocarbon is characterized by negligible electron conductivity, a certain amount of a conductive additive (carbon black) is introduced into the active mass of cathodes. Elementary carbon is formed in the course of discharge and the overall conductivity of the cathode increases. 

Figure 8.21 Optimized structures of initial and docked (R)-mandelic acid-trifluoroacetic acid, and its complex with derivatized p-cyclodextrin. White, light-gray, dark-gray, gray, and black balls represent hydrogen, carbon, nitrogen, fluorine, and oxygen, respectively.

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