Aging behavior and lifetime prediction of PMMA under tensile stress and liquid scintillator conditions

The aging behaviors of PMMA in liquid scintillator at different temperatures of 30 °C, 40 °C, 50 °C and 55 °C under static tensile stress were experimentally investigated with dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC), and the service life of the PMMA was predicted on the basis of the time-temperature superposition approach. The results showed that the higher the aging temperature, the faster the tensile strength of PMMA decreased. Acceleration of aging can be realized by applying high temperatures, and a master curve can be constructed using the time-temperature superposition concept. The linear behavior of the plot of the shift factors versus the inverse aging temperature indicated that the aging mechanism was consistent with Arrhenius's law, and the lifetime of PMMA was predicted to be 25 years at 20 °C.