Effect of radiation-induced oxidative degradation on the non-isothermal crystallization of ethylene-butene copolymer

Abstract

A random ethylene–butene copolymer was irradiated with high ionizing energy in environments with different oxygen concentration. The non-isothermal crystallization process of the materials was studied by differential scanning calorimetry. When the polymer was exposed to radiation under free oxygen ambient, the temperature and the crystallinity degree decreased almost linearly with dose because chain-linking reaction prevails. On the contrary, those thermal parameters increased in the material obtained by irradiating the copolymer in environments with oxygen availability where chain scission reactions dominate. It was also found that, at equivalent irradiation dose, the crystallization rates decreased with the dose at a given cooling rate and with the reduction in oxygen content. The parameters obtained from different applied models also confirm the tendencies observed for the experimental variables.