Free radical reactions in irradiated polytetrafluoroethylene—III. Recombination of alkylfluoride and peroxide radicals : Yu. D. Tsvetkov, Ya. S. Lebedev and V. V. Voevodskii, Vysokomol. soedin. 3: No. 6, 882–890, 1961

Abstract

The kinetics and rate constants of recombination of peroxide and alkylfluoride radicals in irradiated teflon of various degrees of crystallinity were determined with the aid of the ESR method. The recombination was shown to be a second order reaction, the rates ln the amorphous zones of the polymer differing from those in the crystalline zones. The degree of crystallinity of the specimens may be estimated from the linear anamorphoses of the kinetic curves. On the basis of the experimental and reported data on the rate constants, the recombination mechanism of radicals in polymers was discussed. The rate of recombination is apparently determlned by the motion of the chain segments. The anomalously high values of the pre-exponential factors and the compensation effect in the recombination of alkyl radicals were interpreted in terms of a fall in the segment rotation barrier on approaching the melting temperature. (tr- auth)