Reactor Neutron and Gamma Irradiation of Various Composite Materials

Abstract

Polymer matrix composites with nine different resin systems were prepared with S-2 Glass®*-fiber reinforcement. The resins evaluated were epoxy, bismaleimide, and polyimide; all are suitable for vacuum potting, resin transfer molding, filament winding, and preimpregnation. The composite specimens fabricated were 3.2-mm-diameter, unidirectionally reinforced rods. They were tested in torsion to obtain interlaminar shear properties at 295, 76, and 4 K. Specimens from the same resin systems were irradiated at three different total dose levels (4.7 × 10⁶, 4.7 × 10⁷, and 2.3 × 10⁸ Gy) at 330 K and then tested in torsion at 76 K.

The results indicate that (1) properly formulated and cured liquid epoxy systems maintained a high shear strength even at the highest dose levels; (2) some polyimides lost no strength at the higher dose levels, whereas others lost considerable strength; (3) higher molecular-weight epoxy resin systems, although they had a higher strength than the bismaleimide system before radiation, lost this advantage after irradiation.