Creep Behavior of a Carbon-Fiber-Reinforced Thermoplastic Polyimide Resin

The thermal properties, particularly the viscoelastic properties, of a carbon-fiber-reinforced thermoplastic polyimide (CFRTP) resin (AURUM) were studied, and the influence of the change in its crystallinity by heat-treatment was further in vestigated. The static mechanical properties were evaluated by the three-point bending test, whereas the thermal properties were examined in terms of the deflection temperature under loading and the creep properties by the three-point test method. As a result, it was confirmed that the viscoelastic deformation of this CFRTP material was of an Arrhenius linear type in the range of 195 to 265°C, and it was further clarified that blending with fibers brought about marked reduction in viscoelastic properties. In addition, it was found that elevation in crystallinity by heat-treatment effected an improvement in the strength and elastic coefficient of CFRTP but, on the other hand, gave rise to embrittlement of the material. From these results, it was ascertained that this material could become a tailored material by regulation of fiber content and crystallinity.