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Thermo-Oxidative Stability Studies of Celion 6000/PMR-15 Unidirectional Composites, PMR-15, and Celion 6000 Fiber

Studies were conducted to examine the influence of the thermo-oxidative resistance characteristics of the fiber and matrix resin on the thermal stability of composites made from these materials. Celion 6000 graphite fiber, PMR-15 matrix resin, and Celion 6000/PMR-15 unidirectional composites were isothermally aged in air-circulating ovens at 288, 316, 329, and 343 °C. Microscopy (SEM) studies indicate extreme oxidative erosion of the graphite fiber occurs at elevated temperatures in the presence of the polyimide matrix. Activation energies were calculated for the thermal degradation of the three materials. The activation energy of oxidation of the composite was found to be greater than those of the fiber and the matrix resin.