INCREASE OF THE THERMAL STABILITY OF POLYETHYLENE-INSULATED LINES BY IONIZING RADIATION
A copper wire 1 mm in diameter and insulated with 0.5 mm of polyethylene was irradiated by a Co/sup 60/ gamma radiation source of 20000 g-equ Ra in a vacuum as well as by an electron linear accelerntor in the air. The thermal stability of the irradiated samples was determined by the analysis of the thermomechanical curves. The deformation that was attained is a measure of thermal stability at given temperature and load. The lifetime of the workpiece can be estimated from the time dependence of deformation at constant temperature and load. At increased temperatures the deformation is lower, the higher the radiation dose, and remains practically constant up to 250 deg C. The restriction of deformation under a load of 0.5 kg to about half the radial thickness by irradiation with doses of 100-150 Mrad or by irradiation with 1-Mev (15 mu a/cm/ sup 2/) electrons for 2-4 min guarantees the usability of lines above 80 deg C. The final deformation is increased by a load increase without any change of its nature. The line still remains efficient if the load is quadrupled. The deformation is only little temperature-dependent under both long and brief load action. A line with irradiated insulation can be exposed to 180 deg C for at least 4 hrs, and remains efficient for some hours even at 230-250 deg C. Gamma irradiation in vacuo increases the stability at 20 and 90 deg C, while doses of more than 200 Mrad reduce it. The irradiation of 0.4 mm thick samples in the air reduces the relative elongation and also the tensile strength at 20 and 90 deg C. The best strength properties are achieved by irradiation in vacuo with doses of up to 100 Mrad. Tensile strength, resistance to frost, electric breakdown and electrical resistance of a sample irradiated with a gamma dose of 100 Mrad or, equivalently, with 1=Mv electrons for 2-4 min were fully satisfactory. The resistance of line insulation to thermal aging drops with increasing radiation dose. Samples irradiated with electrons are more resistant in this respect than samples irradiated with an equivalent gamma dose. (TCO)
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-18-014570
- OSTI ID:
- 4082024
- Journal Information:
- Tr. Tashkentsk. Konf. po Mirnomu Ispol. At. Energii, Akad. Nauk Uz. SSR, Journal Name: Tr. Tashkentsk. Konf. po Mirnomu Ispol. At. Energii, Akad. Nauk Uz. SSR Vol. Vol: 1
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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IMPROVING THE PROPERTIES OF HIGH POLYMER MATERIALS FOR INSULATED WIRES BY IRRADIATION
Related Subjects
AIR
COBALT 60
COPPER
DEFORMATION
DIAGRAMS
DIELECTRICS
EFFICIENCY
ELECTRIC CONDUCTIVITY
ELECTRON BEAMS
ENERGY
GAMMA RADIATION
HEAT TREATMENTS
METALS, CERAMICS, AND OTHER MATERIALS
POLYETHYLENES
PRESSURE
RADIATION DOSES
RADIUM
SAMPLING
STABILITY
TEMPERATURE
TENSILE PROPERTIES
THICKNESS
VACUUM
WIRES