Thermal Decomposition Behavior of Polyester Fabrics Treated with a Bromine-Containing Compound

Abstract

The thermal decomposition behavior of poly ( ethylene terephthalate) (PET) fabrics containing meso -1,2,3,4-tetrabromobutane (TBB) is investigated using thermogravimetry (TG), differential thermal analysis (DTA), and pyrolysis gas chromatographymass spectrometry (Py-GC-MS). Isothermal TG analysis proves that the presence of TBB has little effect on the thermal decomposition of PET. However, isothermal DTA data reveal that the absorbed TBB participates in some reactions in the condensed phase of PET. On the other hand, Py-GC-MS analysis reveals that bromine atoms exist in the thermal decomposition products of PET. Thus, vinyl groups are generated from PET by β-CH hydrogen transfer, and they then react with hydrogen bromide, which is produced by TBB, to form bromine-containing thermal decomposition products. These facts show why TBB molecules, which have strong affinities for PET segments, are effective for Hame retardation.In our previous paper [4], we studied the relationship between flame retardation and the phase transition behavior of poly ( ethylene terephthalate ) ( PET ) fabrics treated with a bromine-containing flame retardant, me.so-1,2,3,4-tetrabromobutane (TBB), using differential scanning calorimetry. Our work revealed that the depression of the melting initial temperature is directly proportional to the effect of flame retardation. When we applied Flory's equation for depressing the melting point in polymer-diluent systems to the PET-TBB system, our results suggested that TBB molecules, which have strong affinities for PET segments, markedly retard flammability. Thus, TBB works in the condensed phase of PET fabric.In contrast, Koch et al. suggested that bromine-containing flame retardants work mainly in a gas phase and not in a condensed phase, using their thermogravimetric (TG) data from measurements at a constant heating rate [3]. They discussed the mechanism of flame retardation based on the temperatures at which flame retardants are liberated, using a comparison with the thermal decomposition temperature of PET. However, the temperature condition of TG analysis is considered to be quite different from that of actual combustion. In the case of continuous combustion, PET fibers near flames are heated rapidly, and the inflammable vapor evolving from the surfaces of molten PET is continuously supplied as a fuel. Granzow et al. measured the surface temperature of burning PET samples by means of a miniature thermocouple embedded in the polymer. They reported that the surface temperature of burning PET reaches about 380°C, and when 4% red phosphorus is added, it rises to about 450°C [ ]].Considering that the surface temperature of buming PET is constant, the mechanism of flame retardation should be investigated based on the TG data obtained from isothermal measurements rather than non-isothermal ones. Therefore, in this study, we have investigated the thermal decomposition of PET fabrics treated with TBB by comparing isothermal TG and differential thermal analysis (DATA) measurements with non-isothe...

Durable flame‐retardant treatment of polyethylene terephthalate (PET) and PET/cotton blend using dichlorotribromophenyl phosphate as new flame retardant for polyester

“…However, the finish with TBPP was withdrawn due to its mutagenic and carcinogenic properties, despite its excellent performance and easy application. Developments of new flame retardants based on halogen and/or phosphorous compounds and the applications of previously known chemicals for PET fibers were extensively investigated,2–4 for example, condensation polymers of bisphenols and phosphorodichloridates,5 polyphosphoroamides,6 polyvinylbromide,7 meso‐1,2,3,4‐tetrabromobutane,8, 9 antimony oxide with brominated polycarbonate or decabromodiphenyl‐ oxide,10, 11 and so forth.…”