Thermal oxidation of fractionated polypropylene in solution

摘要

AbstractThermal oxidation of fractionated polypropylene was carried out in trichlorobenzene under atmospheric oxygen at 125°C with conventional oxygen uptake. The oxidizability of the polymers is discussed on the basis of the oxygen uptake curves and the properties of the polymers. Fractions of atactic polypropylene oxidized easily at the initial stage of the oxidation and showed neither autoxidation phenomena nor the induction period observed in the isotactic polymer. Hydrogenation of the ether‐soluble fraction by a Wilkinson catalyst gave a polymer which was, according to infrared spectrometry, free from impurity groups such as hydroperoxide, carbonyl, and unsaturation groups. The hydrogenated fraction was more stable to thermal oxidation than the unhydrogenated fraction and showed an induction period. The results indicate that the initiation process of the oxidation of polypropylene is apparently dependent on the impurities such as hydroperoxide, carbonyl, and unsaturation and that stereoregularity of the polymer affects the kinetic dependence of the oxidati