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Characterization of flame‐retarded polymer combustion chars by solid‐state 13 C and 29 Si NMR and EPR
Author(s) -
Gilman Jeffrey W.,
Lomakin Serge,
Kashiwagi Takashi,
VanderHart David L.,
Nagy Vitaly
Publication year - 1998
Publication title -
fire and materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.482
H-Index - 58
eISSN - 1099-1018
pISSN - 0308-0501
DOI - 10.1002/(sici)1099-1018(199803/04)22:2<61::aid-fam639>3.0.co;2-s
Subject(s) - char , flammability , polymer , combustion , vinyl alcohol , fire retardant , chemistry , electron paramagnetic resonance , materials science , chemical engineering , polymer chemistry , polypropylene , cellulose , organic chemistry , nuclear magnetic resonance , physics , engineering
We report here on the results of our continuing effort to study the flame‐retardant mechanism of silica gel and potassium carbonate. These additives reduce the flammability of a wide variety of common polymers such as polypropylene, nylon, polymethylmethacrylate, poly(vinyl alcohol), and cellulose. In an effort to determine how these additives reduce polymer flammability, we have used electron paramagnetic resonance spectroscopy and solid‐state 13 C and 29 Si nuclear magnetic resonance spectroscopy to characterize the combustion chars or residues. These data indicate that, in the case of poly(vinyl alcohol), the additives do not change the type of char formed, but they do change the rate of char formation relative to the rate of fuel generation. We also found that, using only CP/MAS 13 C NMR, there can be significant intensity distortions which complicate interpretation, if the char is hydrogen depleted and contains paramagnetic centres. © 1998 John Wiley & Sons, Ltd.