چكيده لاتين :
UV of radiation of polymers causes photo-oxidation degradation which results in loss physical and mechanical properties and limits their applications. In order to study long term stability of the radiated cross-linked polyethylene films on outdoor exposure, low density polyethylene (PE) in pure form mixed with photostabilizers and antioxidant (PE-st) was irradiated by electron beam in air at 30-300 kGy doses. The irradiated samples were exposed to the outdoor condition for 24 months.The gel content of irradiated samples demonstrated that cross-linking reaction has occurred and caused the increasing of mechanical properties. The results of FTIR measurments show that upto 200 kGy carbonyl formation is negligible. Increase of carbonyl groups and decrease of mechanical properties in irradiated and outdoor exposed samples are indication of degradation progress in cross-linked polymer structure. In addition, some of the irradiated samples were buried under the soil. Observation of unchanged chemical structure of buried samples after 24 months, proves that UV light and oxygen are the main factors of their degradation.
