SynopsisThermal oxidation of isotactic polypropylene (PP) at 220 and 280°C in air was studied. Gas chromatography-mass spectrometric analysis was used to separate and identify the volatile products of PP oxidation. Twenty-three products were identified and 15 substances were quantified. The aldehydes are the principal products formed, followed by ketones, acids, and alcohols. The main organic product quantified was acetaldehyde. The volatile organic products formed constitute about 3% of the amount of water formed. The relative amounts of the most volatile products formed in the range 220-280°C are practically independent on the temperature of oxidation. The mechanism of formation on the oxidation products is discussed.