Kinetics of the thermal oxidation of isotactic polypropylene by infrared spectroscopy

Abstract

The thermal oxidation of a film of isotactic polypropylene was studied using infrared spectroscopy. Reaction temperatures varied from 120"-150 "C. and oxygen concentrations from 7 -1 0 0~0 , by volume. A reaction scheme was postulated and kinetic expressions were developed therefrom. These expressions could explain very well the experimental results obtained. An activation energy of 31 f 1 kcal./mole was obtained for the initiation process whereas a value of 22 & 1 kcal./mole was obtained for the process involving the formation of non-volatile oxygenated substances. ZUSAMMENFASSUNG:Mit Hilfe der Infrarotspektroskopie wGrde die thermische Oxydation eines isotaktischen Polypropylenflms studiert. Die Reaktionstemperatur wurde von 120-150 "C variiert und die Q,-Konzentration von 7-100 Vol.-yo. Ein Reaktionsschema wurde aufgestellt, und daraus wurden kinetische Gleichungen abgeleitet. Diese Gleichungen standen in sehr guter Ubereinstimmung mit experimentellen Ergebnissen. Fur den InitiierungsprozeB wurde eine Aktivierungsenergie von 31 & 1 kcal/Mol gefunden, wahrend 22 ?c 1 kcal/Mol fiir die Reaktion angegeben wurden, in der die Bildung von nicht-fluchtigen Oxydationsprodukten erfolgte.

Physicochemical changes in stabilized, orientated polypropylene films during the initial stages of thermal oxidation

“…This last result followed aging at lower temperatures of 60-90°C compared with the higher ranges used by Stivala et al 13 Similar values have been reported for pure oxygen oven-aged p~lypropylene.~,'~ Our E values are consistently lower for both stabilized and unstabilized polypropylene than these cited results. …”

Recent aspects of the uncatalyzed thermal oxidation of isotactic polypropylene

“…Sample films were held to a NaCl disc with fine nichrome wire and assembled in a cell as previously described (1). Known concentrations of dry mixtures of 0, and N, were metered into the temperature-controlled cell at a constant flow rate.…”

Kinetics of autoxidation of isotactic polybutene‐1 by infrared spectroscopy

“…[2][3][4] In this paper, we present an extension of the previously reported mathematical treatment to the case of isotactic polybutene-1 (IPB). The experimental data were obtained from the quantitative estimation of carbonyl groups by infrared spectro~copy.…”