Polymer reactions, 8. Oxidative pyrolysis of poly(propylene)

Poly(propylene) has been oxidized at temperatures between 240 and 289°C. The products were GC separated and on‐line identified by an interfaced GC peak identification system. The major products are CO 2 , H 2 O, acetaldehyde, acetone, butanal, formaldehyde, methanol and other ketones and aldehydes. Most of the products can be accounted for by well‐known reactions of alkoxyl and peroxyl radicals; the major products are derived from the secondary alkoxy and peroxy species. Oxygen starvation is manifested in diffusion limited products of olefins and dienes, and the increase of CO 2 and H 2 O formation in pure oxygen atmosphere. The first order rate constant at 240°C is 2,4·10 −3 S −1 with an overall activation energy of ca. 16 kcal·mol −1 (67 kJ·mol −1 ). If one assumes the oxidative pyrolysis to share the same reaction pathways as autoxidation at lower temperatures, then the observed rate constants and activation energy may be calculated from kinetic parameters measured earlier for autoxidation of poly(propylene) from 71 to 140°C. Good agreement was obtained implying a similarity of oxidative degradation of the polymers spanning a large temperature range.