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Flammability resistance synergism in BPA polycarbonate–silicone block polymers
Author(s) -
Kambour R. P.
Publication year - 1981
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1981.070260311
Subject(s) - char , flammability , pyrolysis , materials science , chemical engineering , polymer , polycarbonate , limiting oxygen index , silicone , polymer chemistry , composite material , chemistry , organic chemistry , engineering
Abstract The synergism in limiting oxygen index found in BPA carbonate–dimethylsiloxane block polymers (BPAC/DMS) is correlated with a rise in yield of pyrolytic char and an improvement in char oxidation resistance. These changes in turn are related to a peaking of fractional silicon retention in the char at a resin composition of 50 mole % DMS. This behavior, the fine dispersion of silicon in the char, and analyses of the pyrolysates suggest that an important feature of char formation in the block polymers is a polycondensation reaction between pyrolysis products from the two blocks. In addition to the role of chars in withholding fuel from the flame, they are thought to function effectively as thermal insulators.