Unpaired Electrons in Carbon Blacks
作者:
R. L. Collins,
M. D. Bell,
Gerard Kraus,
期刊:
Journal of Applied Physics
(AIP Available online 1959)
卷期:
Volume 30,
issue 1
页码: 56-62
ISSN:0021-8979
年代: 1959
DOI:10.1063/1.1734975
出版商: AIP
数据来源: AIP
摘要:
An appreciable concentration of unpaired electrons has been found in colloidal carbon blacks through the application of electron spin resonance spectroscopy. The unpaired electrons in a typical channel process carbon black, Spheron 6, have been studied by noting the changes in the electron spin resonance spectrum produced by heat treatment (HT) to 3000°C and by various degrees of evacuation of the sample. The results indicate that the unpaired electrons in the original material are mobile &pgr; electrons, which are stabilized by condensed aromatic ring structures. Their concentration decreases slowly to 750°C HT and then declines more rapidly and vanishes above 1400°C HT. A different species of unpaired electrons arises at 1400°C HT. These are believed to be immobile &sgr; electrons resulting from broken carbon‐carbon bonds at lattice defects. The unpaired electrons present in several commercial carbon blacks have been examined and are believed to be &pgr; electrons also. A tentative theory of the origin of the unpaired electrons is given.
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