Title :
Evaluation of residual lifetime of LDPE degraded radiation by time-temperature superposition method
Author :
Kim, Ki-Yup ; Lee, Chung ; Ryu, Boo-Hyung ; Lim, Kee-Joe
Author_Institution :
Korea Atomic Energy Res. Inst., South Korea
Abstract :
A novel method has been proposed to determine the residual lifetime of low density polyethylene (LDPE) by time-temperature superposition (TTS) using a dynamic mechanical analyzer (DMA). The principle of this new method is to detect the change in response of polymeric materials to multi-frequency dynamic loading over a glass transition interval. LDPE was irradiated with gamma rays up to 1000 kGy at a dose rate of 5 kGy/hr in the presence of air at room temperature. The glass transition temperatures of irradiated samples were tested and compared with TGA and DMA methods. The inter-relationship between TGA and TTS methods for lifetime prediction was investigated. For radiation degradation of polymeric materials, TTS method can be a useful tool to predict the residual lifetime
Keywords :
dynamic response; elastic moduli; gamma-ray effects; glass transition; insulation testing; life testing; polyethylene insulation; stress relaxation; thermal analysis; 1000 kGy; DMA; LDPE; TGA; TTS; dynamic mechanical analyzer; gamma ray irradiation; glass transition interval; mechanical loss modulus; multi-frequency dynamic loading; radiation degradation; reduced stress-relaxation curves; residual lifetime; room temperature; time-temperature superposition; Atomic measurements; Elasticity; Glass; Organic materials; Plastic insulation; Polyethylene; Polymers; Speech synthesis; Temperature dependence; Thermal degradation;
Conference_Titel :
Electrical Insulating Materials, 2001. (ISEIM 2001). Proceedings of 2001 International Symposium on
Conference_Location :
Himeji
Print_ISBN :
4-88686-053-2
DOI :
10.1109/ISEIM.2001.973584
