Studies on the mechanism of combustion and pyrolysis of flame retarded PET fibers

摘要

The products of pyrolysis of untreated and flame retarded PET Fibers have been studied using gas chromatography/mass spectrometry technique combining with CONE data. A mechanism of two-phase pyrolysis for PET degradation is proposed. The first step in the degradation is the ester scission reaction to give a carboxylic acid and olefinic end groups. Further ester scission can lead to the formation of lower weight pyrolytic products. At the same time, a cross-linking cyclization reaction occurred and ultimately produce a kind of cycloolefin structure. Brominated aromatic polymer flame retardant (FR-B) involved only gas-phase mechanism, while brominated phosphate compound (FR-A) and polybenzphosphonate flame retardant (FR-C) in volved both gas-phase and solid-phase mechanism.