Green Polyethylene in Harsh Environments: Gamma-irradiation Effects

Bio-based linear low-density polyethylene (green LLDPE) composites are used as electrical jackets/insulator for cables. Assessments of gamma-irradiation (Co-60) effects on these materials are of interest as they might be used in nuclear power plants (NPPs). Brazilian sugarcane juice-based green LLDPE composite electrical jackets were irradiated until 1000 kGy and analyzed for thermal stability and mechanical characteristics. Thermogravimetry analysis (TGA) showed increasing of pyrolysis activation energy (Ea) (under N2) from 42.7 ± 4.2 kJ/mol in unirradiated samples to 72.8 ± 4.6 kJ/mol after 60 kGy dose, as resulted of radiation-induced effects. FTIR spectra evidenced radiation-induced formation of conjugated C=C bonds after 250 kGy dose. Tensile stress and Young modulus did not change significantly until 150 kGy dose, whereas elongation at break decreased and reached 50% at 91 kGy dose. These results suggest that green LLDPE might withstand radiation damage through a NPP operating life (~ 40 years).