MASS-SPECTROMETRIC STUDIES OF THE REACTIVITY OF ANTIMONY TRIOXIDE WITH HALOGENATED FLAME RETARDANTS IN THE PYROLYSIS OF PLASTICS

A mass spectral study of the pyrolytic degradation of a number of halogenated flame retardants, intrinsically flame-retarded polymers, and halogenated model compounds alone and in the presence of antimony trioxide has been conducted to investigate the role of the putative synergist Sb2O3. Each system was heated within the ion source of a mass spectrometer using a specially designed pyrolysis probe so that degradation products could be ionized and detected directly. The in-source system, while producing multicomponent mass spectra, eliminated the potential loss of classes of compounds that can be associated with gas chromatographic separation of pyrolysis products prior to mass analysis. Mass spectra obtained during pyrolysis of the polymers and model compounds show that degradation occurs with the formation of halogen radicals, hydrogen halides, and/or halogen dimers. Mass spectra obtained during pyrolysis of the polymers and model compounds in the presence of Sb2O3 show that in some cases degradation resulted in the formation of antimony halides. In others the degradation products were the same as those formed in the absence of Sb2O3. Analysis of the data for all the systems shows that antimony halide formation in these flame retarded systems is dependent not only on the presence of the halogen and Sb2O3 but also on the availability of labile hydrogen. © 1990.