Polymeric Carbon Graphite

The variance of property with angle of applied force, light, magnetism, and so on is called anisotropic behavior. Calcite is anisotropic in its crystal structure, resulting in a dependency of its interaction with light with the angle of incidence of the light. 

---

Dagli, G., Sung, N.H. (1989). Properties of carbon/graphite fibers modified by plasma polymerization. 

Similarly, the Cls XPS spevctrum of each compound (WC, W2C, W03) shows consistent surface properties. For WC, the C/s spectrum is apparently composed of two main peaks one at 284.5 eV due to polymeric carbon (CHV) and one at 283.2 eV due to carbidic carbon, as assigned by Bonzel et al.13 (Figure 18.2). For W2C, the Cls spectrum shows only one broad peak at 284.4 eV which probably includes carbidic, polymeric and amorphous or graphitic carbon, the latter at 285 eV.13 For the oxide precursor W03, the same broad peak for the Cls level is reproduced but with a visible shift of the maximum to 285 eV. 

Yoshikawa M, Shimada H, Tsubouchi K, and Kondo Y. Specialty polymeric membranes. 12. Pervaporation of benzene/cyclohexane mixtures through carbon graphite-nylone 6 composite membranes. J Membr Sci 2000 177 49-53. 

Polymeric Packings. Graphitized carbon or mixed copolymers are used as polymeric packing (e.g., polystyrene-divinylbenzene) or further derivatized with ion-exchange or C4, C8, or C18 functional groups. Columns filled with these packings feature levels of performance comparable to those of silica-based columns and are stable from pH 2 to 13. 

Examples of the use of these sorbents and their applications will be given in Chapter 7. Finally, a good review of examples of multiresidue extractions of compounds of environmental interest using polymeric and graphitized-carbon sorbents is given by Font and co-workers (1993). 

Porous graphitic carbon is synthesized by a multistep chemical and thermal treatment from organic monomers deposited in the pores of a silica gel particle template and subsequently subjected to polymerization, carbonization, dissolution of the silica template and graphitization [170,172]. The silica gel template allows optimization of the adsorbent particle size, porosity and surface area for liquid chromatography. The selection of monomers and thermal treatment is responsible for the mechanical strength, high purity and absence of significant microporosity. Commercially available materials have particle sizes of 5 or 7 xm, a mean pore diameter of 25 nm and a surface area of 100-120 m /g. 

For metal or resin impregnated carbon.graphite materials, the extent of polymerization, cure cycles, and degradation can be assessed by measuring electrical resistance of the resin [lOlj. For example, the internal viscosity of a polymer can be determined by monitoring the electrical resistivity as a function of temperature. Electrical and electromagnetic properties of composites as well as NDT techniques are described next. 

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. 

The radial distribution function of polymeric carbon prepared from maleic anhydride by plasma deposition by the present authors is shown in Fig. 12 and the peak positions are listed in Table 1. The peaks are situated at 1.44 and 2.9 A, which do not match the peak position of graphite. The peak positions of carbon samples prepared at 600 C are found to be 1.4 and 2.8 A. It is clear from Fig. 12 that there is no layered structure because the region between the second and third peaks is very flat. In addition, the behavior of the radial distribution function with distance cannot be explained using other carbon models, e.g., C 1120, C 340, C 356, and C 519 suggested by Beeman et al. [46,47]. 

---