| Résumé | The reactions of gaseous sulfur dioxide with partially oxidized polypropylene and polyethylene have been investigated by iodometry and by Fourier Transform Infra-red ( FTIR) spectroscopy. Comparison was also made with chemical changes observed in model liquid hydroperoxides which were analysed by FTIR, nmr and ultraviolet-visible, spectroscopies. Reaction of macro- and model hydroperoxide groups with SO₂ proceeds by two consecutive reactions which occur in varying proportions depending upon the SO₂/hydroperoxide ratio. Because of this, the use of the SO₂ reaction products detected by infra-red (believed to be hydrosulfates) to quantify hydroperoxide is unreliable and gives little improvement in detection level over direct measurement of hydroperoxide by infra-red. Exposure to SO₂ and then gaseous ammonia produces some ammonium sulfate from hydroperoxide groups. The ammonium sulfate can be detected with high sensitivity by infra-red, but the stoichiometry of its generation is again variable. |
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