Physical and chemical aging in PMMA and their effects on creep and creep rupture behavior

Samples of PMMA were aged at 80°C for between 1 h and 254 days and tested in creep in uniaxial extension at large stresses and at room temperature. Both chemical and physical aging effects were found to be important in determining the failure behavior of the samples. This behavior was found to be describable within the context of a commonly used failure criterion that the time to failure multiplied by the strain rate at failure is constant. The creep behavior was found to follow classical time–aging time and time–stress correspondence principles.