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Reaction Mechanisms of Silicon Carbide Fiber Synthesis by Heat Treatment of Polycarbosilane Fibers Cured by Radiation: II, Free Radical Reaction
Author(s) -
Sugimoto Masaki,
Shimoo Toshio,
Okamura Kiyohito,
Seguchi Tadao
Publication year - 1995
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1995.tb08898.x
Subject(s) - radical , electron paramagnetic resonance , pyrolytic carbon , pyrolysis , oxygen , materials science , curing (chemistry) , silicon carbide , photochemistry , fiber , yield (engineering) , polymer chemistry , chemistry , composite material , organic chemistry , physics , nuclear magnetic resonance
Silicon carbide (SiC) fibers were synthesized by the pyrolysis of radiation‐cured polycarbosilane (PCS) fibers. The pyrolytic reaction was analyzed through free radicals by electron spin resonance (ESR). Free radicals on Si and C atoms were produced in the pyrolysis, and their yield as a function of reaction temperature depended on the oxygen content in the cured PCS fibers. There were two temperature ranges for the reactions related to Si and C atoms in PCS fibers. The radical concentration reflects the rate differences between the radical formation by the cleavage of Si‐H and C‐H bonds and the decay by recombination of radicals. The reaction of Si‐H was strongly influenced by the oxygen content in the cured PCS fibers, and the decay rate of radicals decreased with an increase of the oxygen content in PCS fibers introduced in the curing process.