Effects of γ-radiation on the performances of optically transparent shape memory polyimides with a low glass transition temperature

Recently, shape memory polyimides (SMPIs) with varying glass transition temperature (Tg) and optical transparency have been developed widely. While, rare reports were focused on the evaluation of the durability of SMPIs in the complex and volatile space environments. This paper presents the simulated γ-radiation accelerated experiment of two kinds of optically transparent SMPIs with a Tg of 178 °C and 196 °C, respectively. The effects of γ-radiation on chemical structure, optical transmittance, shape memory behavior, thermomechanical property, thermal stability, and mechanical properties were investigated. Although SMPIs have endured γ-radiation for 1 × 106 Gy, the chemical structure, Tg, optical transmittance, thermal stability, and the shape memory behavior remained unchanged. Also, SMPIs with a Tg of less than 200 °C could maintain their high tensile strengths and elongations at break (>109.5 MPa, >7.6%) after being exposed to 1 × 106 Gy γ-radiation, which shows great potential application in space active deformation structures and devices.