Long-term thermal stability of carbon fibre-reinforced addition-type polyimide composite in terms of compressive strength

Abstract

A previously developed carbon fibre-reinforced addition-type polyimide composite material was exposed to temperatures of 240, 270 and 300 °C in air for 3000 h to study its long-term stability in terms of its compressive strength. The in-plane shear modulus, compressive failure mode and transverse crack density were also evaluated to determine whether a degradation process induces a decrease in the compressive strength of a high-temperature polymer matrix composite having a laminated configuration of [90/0]_4s. The carbon fibre-reinforced polyimide composite exhibited excellent thermal stability in terms of its compressive strength after being subjected to ageing at 240 °C for 3000 h and at 270 °C for 2000 h, with degradation becoming significant at 300 °C. The compressive strength decreased only when the surface degradation caused the 90° plies sandwiching the 0° plies to degrade severely.

Keywords:

• aromatic polyamide
• high-temperature polymer matrix composite
• long-term thermal stability
• compressive strength
• micro buckling

Acknowledgements

Our deepest appreciation goes to all persons concerned in this program.