Citation

Wang JQ, Tu HB, Jiang QJ. J. Fire Sci. 1995; 13(4): 261-280.

Copyright

(Copyright © 1995, SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Crosslinking and charring in the condensed phase of polymers during heating, processing, and/or burning are of central importance in their flame retardance and smoke suppression and in formulating polymeric composites. Combining with thermal analysis techniques (TGA, DSC), ethylene-vinyl acetate (EVA) copolymers and polyethylenes (HDPE, LDPE) with/without inorganic phosphorus-containing additives, were selected as model systems for XPS studies of the charring process. A new parameter, T(gr), the transition temperature from mesophase to graphitic structure (graphite-like structure, GLS) of the char has been well-defined and determined by combination of core levels and valence bands in XPS. The reason for T(gr) to be selected as a likely supplementary parameter for characterizing polymer charring in condensed phase is two-fold: 1) a clear-cut phase transition; 2) at which temperature a highly crosslinked network results. A special emphasis in the paper has been given to the roles of the oxygen atoms either introduced from an adventitious atmosphere or inherent Ac group itself. Along this line some features in both thermal degradation and flame retardance of polymers have been rationalized in terms of transition temperature T(gr).