Chemistry of carbonization

Lewis, I.C.

doi:10.1016/0008-6223(82)90089-6

Cited by 252 publications

(109 citation statements)

References 57 publications

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“…For example, structures which contain five membered rings can produce either graphitising or non-graphitising carbon. 54 In fact, it is generally believed that the physical properties of the precursors, and the conditions under which pyrolysis is carried out, are more important than chemical structure in determining whether the final carbon is graphitising or non-graphitising.…”

Section: Discussionmentioning

confidence: 99%

Structure of non-graphitising carbons

Harris¹

1997

International Materials Reviews

198

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Despite many years of research, the detailed atomic structure of many important carbon materials remains poorly understood. In particular, the structure of those carbons which can not be transformed into graphite by high temperature heat treatment has never been clearly established. These non-graphitising carbons are of considerable commercial importance in a variety of fields, and a better understanding of their structure is clearly needed. Recently, it has been suggested that non-graphitising carbons may have a microstructure which is related to that of fullerenes. In the present paper, the evidence for this will be considered in detail and the advantages of the new model over previous models of non-graphitising carbons will be discussed. As well as microporous nongraphitising carbons, other forms of carbon including glassy carbon and carbon fibres will be considered.IMRj304 IntroductionAlthough graphite is the most stable form of carbon at normal temperatures and pressures, it is a remarkable fact that many carbons can not be transformed into crystalline graphite even at temperatures of 3000°C and above. The so called 'non-graphitising' carbons tend to be hard, low density materials, with isotropic, microporous structures. 1 -6 In contrast, graphitising carbons are soft and non-porous, with densities much closer to that of crystalline graphite. Nongraphitising carbons can develop exceptionally high surface areas when 'activated' by treatment with a mild oxidising agent, and the resulting activated carbons are widely used as adsorbents and as catalyst supports. 4 -6 Despite their commercial importance, however, the detailed structure of these carbons at the atomic level is still poorly understood. The traditional view is that the microstructure consists of twisted networks of carbon layer planes crosslinked by bridging groups, explaining both their hardness and their resistance to graphitisation, 2 but the precise nature of such bridging groups has never been properly established. Earlier suggestions that Sp3bonding may be present in non-graphitising carbons do not appear to stand up to detailed analysis, as discussed in the 'Problems with early models' section later. The relatively recent discovery of the fullerenes,7-9 and subsequently of related structures such as carbon nanotubes 10 -12 and nanoparticles,13,14 has given us a new perspective on Sp2 bonded carbon structures. Most importantly, we now know that carbon structures containing non-six membered rings can be highly stable. It therefore seems worth considering the idea that microporous non-graphitising carbons may be fullerene-like in nature. Recent work has provided support for this view by showing that high temperature heat treatments can transform microporous carbons into fullerene like nanoparticles. 15 The purpose of the present paper is to consider further the evidence that non-graphitising carbons contain fullerene related elements. In addition to microporous carbons, a related class of non-graphitising carbon known as glassy carbon will also...

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Section: Discussionmentioning

confidence: 99%

Structure of non-graphitising carbons

Harris¹

1997

International Materials Reviews

198

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“…Coal has various chemical bonds and consists of 3D cross-linked macromolecules. [9][10][11] In particular, Fourier transform infrared spectroscopy (FT-IR) has extensively been employed to investigate the changes in coal structure during carbonization since FT-IR provides huge amount of valuable information on the chemical composition and structure of coals. [12][13][14] Numerous studies previously dealt with chemical functional groups of various coals using FT-IR.…”

Section: Introductionmentioning

confidence: 99%

Changes of Aromatic CH and Aliphatic CH in In-situ FT-IR Spectra of Bituminous Coals in the Thermoplastic Range

2015

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“…Browning, a Maillard-type reaction, occurs at low levels of available water; therefore, it is common in dry cooking methods, such as grilling, in which the surface layer is dehydrated. Sustained heating of dry surfaces eventually results in carbonization, i.e., thermal conversion of organic materials to carbon (Lewis, 1982), and is usually accompanied by the generation of smoke. During heating, the surface of food first turns brown, following which the surface blackens as it burns (Rosenthal, 2003).…”

Section: Introductionmentioning

confidence: 99%