Professor, The Research Institute for Iron, Steel and Other Metals, Tohoku University, Sendai,
Group leader, Lawrence Livermore National Laboratory, Livermore, CA
Research scientist, Tokyo Institute of Technology, Yokohama,
Senior scientist, Los Alamos National Laboratory, Los Alamos, NM
Pages: 13 Published: Jan 1987
Polyimide films are insulating plastic materials that are useful over a wide temperature range and the most radiation resistant of the polymers. In this paper, mechanical property changes of the polyimide film, KAPTON, caused separately by 14-MeV neutrons and by cobalt-60 gamma rays are examined in detail. Miniature tension specimens of 3-mil-thick film were irradiated at Rotating Target Neutron Source-II and at the Cobalt-60 Pool of Lawrence Livermore National Laboratory at room temperature to a maximum neutron fluence of 1.6 × 1022 n/m2 and a maximum gamma dose of 8.6 × 107 Gy, respectively. Neutron fluences greater than 1 × 1021 n/m2 and gamma dose greater than 2.2 × 107 Gy caused a reduction in total elongation of the film. At our highest tested neutron fluence of 1.6 × 1022 n/m2, the elongation dropped to less than one-fifth and the fracture stress dropped to one-third of the unirradiated value. It was found that 14-MeV neutrons were about eight times more effective than cobalt-60 gamma rays in producing mechanical property changes when compared on the basis of absorbed dose. Color changes induced by irradiation were also examined.
polyimide, irradiation effects, neutron irradiation, gamma ray irradiation, mechanical properties
Paper ID: STP25682S