The below-break tensile properties (tensile modulus, stress decay, and residual extension) of carbon-arc- and gamma- irradiated Nomex fibers were examined after extensions of 2% and 5% held for 0-5 min under both air-dry and wet conditions. Exposure to 15.0 Mrad of gamma radiation resulted in negligible change in the below-break tensile properties, whereas exposure to even 6.25 hr of uv radiation resulted in marked deterioration of these properties. The below-break tensile properties were impaired by wetting, but this impairment was not changed markedly by the radiation exposures. The property changes of the Nomex fibers are contrasted with those previously described for aliphatic nylons.
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