Natural and Synthetic Graphite

Property Modifiers. Property modifiers can, in general, be divided into two classes nonabrasive and abrasive, and the nonabrasive modifiers can be further classified as high friction or low friction. The most frequently used nonabrasive modifier is a cured resinous friction dust derived from cashew nutshell Hquid (see Nuts). Ground mbber is used in particle sizes similar to or slightly coarser than those of the cashew friction dusts for noise, wear, and abrasion control. Carbon black (qv), petroleum coke flour, natural and synthetic graphite, or other carbonaceous materials (see Carbon) are used to control the friction and improve wear, when abrasives are used, or to reduce noise. The above mentioned modifiers are primarily used in organic and semimetallic materials, except for graphite which is used in all friction materials. 

The selected value is essentially the same as that obtained by Greenberg and Hubbard (2) in their thorough calorimetric study of the combustion in fluorine of natural and synthetic graphite. Their results is confirmed by the data of Domalski and Armstrong (3) for combustion of graphite-Teflon mixtures. Reliable data (1 ) also link CP (g) with HF(n HgO), NPg(g) and CgPACpolymer). Armstrong ( , 3) critically reviewed the more uncertain data which were omitted from the adjustment. 

Carbonaceous lubricants are used in most friction materials as a cost-effective way to control friction material performance, wear, and NVH characteristics. Commonly used carbonaceous lubricants are natural and synthetic graphites and metallurgical and petroleum cokes. 

U.S. Pat. No. 6,702,969 [27] discloses a composite material prepared by mixing a thermoset resin, such as phenolic resin, urea resin, melamine resin, epoxy resin, urethane resin, and mixture thereof, to bind wood pieces and a filler, such as natural and synthetic graphites, metal, carbon, and other similar compounds and then-mixtures. 

Among so many kinds of carbonaceous materials, the practical anode materials most widely used in commercialized lithium-ion batteries can be roughly classified into three categories hard carbon, and natural and synthetic graphite. All these types of carbons have different advantages and disadvantages, which will be explained in the following concrete examples. 

Kavanagh A, Schogl R, The morphology of some natural and synthetic graphite, Carbon, 26 (1) 23-32, 1988. 

Ambrosi, A., Chua, C. K., Khezri, B. et al. 2012. Chemically reduced graphene contains inherent metallic impurities present in parent natural and synthetic graphite. Proc. Natl. Acad Sci. U. S.A 109 12899-12904. 

The majority of carbons produced for commercial use, that is as electrodes and nuclear graphite, are produced from cokes, coals or existing natural or synthetic graphite as follows ... 

The carbon raw material in the form of coke, coal or natural or synthetic graphite is ground and sieved (following calcination at 700-1300°C to control volatiles, if necessary) to give a desired particle size distribution. The distribution depends upon the size of the artifact to be formed and the method of forming. 

Natural graphite and synthetic graphite were used as fillers for the manufacture of conducting composite materials by the polymerization filling technique [24, 53-56], The manufacture of conducting polymer composite materials by this technique on the basis of some kinds of carbon black is also known [51, 52],... 

Previous studies focusing on deposition of Cu [6, 15] or Ni [16] coatings and deposits on natural and synthetic graphics relied on an electroless plating method [25]. In this method many different chemical solutions are used in multiple steps to treat the graphite surface, such as... 

Electrochemical oxidation of natural and synthetic DNA performed at pyrolytic graphite [16] and glassy carbon [3-6,17,18] electrodes showed that at pH 4.5 only the oxidation of the purine residues in polynucleotide chains is observed. Using differential pulse voltammetry, the less positive peak corresponds to the oxidation of guanine residues and the peak at more positive potentials is due to the oxidation of adenine residues. 

Both natural graphite and synthetic graphite powder may be used. 

FIGURE 7.19 Scanning electron microscope pictures of a pitch-based hard carbon (a), graphitized MCMB 25-28 (courtesy of Osaka Gas Chemical Co.) (b), coated natural graphite (c), and synthetic graphite (d). 

Electrochemical oxidation of natural and synthetic nucleic acids at carbon electrodes pyrolytic graphite [34], paraffin-wax-impregnated spectroscopic graphite [35] and glassy carbon [36, 37] has been studied. It was shown that at pH 4.5 the electrochemical activity of nucleic acids is conditioned by the presence of purine residues in polynucleotide chains. 

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. 

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