AGING AND DEGRADATION OF POLYOLEFINS - 1. PEROXIDE-INITIATED OXIDATIONS OF ATACTIC POLYPROPYLENE.

Abstract

Efficiencies of polymer radical production by thermal decomposition of di-tert-butylperoxy oxalate (DBPO) have been measured in bulk atactic PP at 25-55 C; they range from 1 to 26%, depending on left bracket DBPO right bracket , temperature, and presence of oxygen. The fraction that escapes gives hydroperoxide in a reaction that is half order in rate of initiation. In interactions of polymer peroxy radicals, in or out of the cage, about one-third give dialkyl peroxides and immediate chain termination, two-thirds give alkoxy radicals. Concentrations of free polymer peroxy radicals have been measured by electron spin resonance and found to be very high.