Influence of the irradiation conditions on the effect of radiation on polyethylene

Two types of polyethylene, low density (LDPE) and high density (HDPE), as well as low density polyethylene containing an antioxidant were subjected to gamma-irradiation in the presence of air and in water. The irradiated polymers were studied using IR spectrophotometric analysis. The radiation induced oxidative degradation was followed through the formation of oxygen containing groups by the development of bands in the 1850-1650 cm(-1) region and double bonds formation by the development of bands in the 1050-850 cm(-1) region. The crosslinking efficiency was determined by measuring the gel content by extraction with xylene. The radiation induced changes in the molecular structure, evolution of oxygen containing species and formation, of vinyl double bonds as well as of the crosslinking efficiency are discussed in terms of the properties of the polymers in an electric field of low strength