Statistical model of thermal degradation of linear polymers

Thermal degradation of a high-molecular-mass linear polymer is revisited for PE in terms of the theory of random ruptures. The polymer → gaseous products process is shown to proceed as a continuous sequence of chemical reactions accompanied by the occurrence of such physical phenomenon as evaporation of the formed fragments of macromolecules. Quantitative estimates suggest that the experimental conditions for vapor formation (pressure, heating rate, geometric dimensions, shape of the test sample, etc.) exert a marked effect on the overall rate of conversion and on the resultant brutto effect of thermal degradation. Hence, comparison of empirical “kinetic constants” of thermal degradation for polymers prepared by different methods and under different temperature-time regimes seems to be incorrect.