Polymer Carbon difference from graphite

Discovery of crystalline solid C60 was actually the finding of a new form of crystalline carbon, being different in dimensionality from graphite, two-dimensional sp2 carbon. It is also different from diamond, three-dimensional sp3 carbon. From this viewpoint, crystalline C60 polymers produced via high-pressure and... 

The hyperbranched polymers are carbon-rich macromolecules and show excellent thermal stabilities. The thermal properties of the hb-PAs are described below as an example. Their thermal stabilities were evaluated by TGA. Figure 3 shows TGA thermograms of some hb-PAs and Table 4 lists their thermal analysis data. The hb-FAs were thermally very stable for instance, hb-P66 lost merely 5% of its weight at a temperature as high as 595 °C. All the polymers, except for hb-F(44-Vl) and hb-F(59-Vl), carbonized in > 50% yields on pyrolysis at 800 °C, with hb-P(45-V) graphitized in a yield as high as 86% (Table 4, no. 3). The thermal stabilities of the hb-PAs are similar to that of Unear pol-yarylenes such as PPP but different from those of Unear polyacetylenes such as PH and PPA. The dramatic difference in the thermal stability is mainly due to the structural difference PPP is composed of thermally stable aromatic rings (Td 550 °C) [108-112], whereas PPA and PH are comprised of labile polyene chains, which start to decompose at temperatures as low as 220 and 150 °C, respectively [113]. The excellent thermal stabilities of the hb-FAs... 

Fillers, or extenders as they are called in the coatings industry, are finely divided solids added to polymer systems to improve properties and reduce cost Fillers are solid additives, different from plastics matrices in composition and structure, which are added to polymers to increase bulk or improve properties In manufactured carbon and graphite product technology, carbonaceous particles comprising the base aggregate in an unbaked green-mix formulation... 

Rao and Sircar [5-7] introduced nanoporous supported carbon membranes which were prepared by pyrolysis of PVDC layer coated on a macroporous graphite disk support. The diameter of the macropores of the dried polymer film was reduced to the order of nanometer as a result of a heat treatment at 1,000°C for 3 h. These membranes with mesopores could be used to separate hydrogen-hydrocarbon mixtures by the surface diffusion mechanism, in which gas molecules were selectively adsorbed on the pore wall. This transport mechanism is different from the molecular sieving mechanism. Therefore, these membranes were named as selective sitrface flow (SSF ) membranes. It consists of a thin (2-5 pm) layer of nanoporous carbon (effective pore diameter in the range of 5-6 A) supported on a mesoporous inert support such as graphite or alumina (effective pore diameter in the range of 0.3-1.0 pm). The procedures for making the selective surface flow membranes were described in [5, 7]. In particular, the requirements to produce a surface diffusion membrane were shown clearly in [7]. 

Most non-graphitic carbons are prepared by pyrolysis of organic polymer or hydrocarbon precursors at temperatures below -1500 °C. Further heat treatment of most non-graphitic carbons at temperatures from -1500 to -3000 °C makes it possible to distinguish between two different types of carbons. 

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