Tensile Creep Failure of Isotactic Polypropylene under the Strain Criterion

Abstract

Tensile creeps of isotactic polypropylene under different loads and at different temperatures were investigated. By analysis of the true strain–time creep curves, the increment of strain during the secondary creep is found to be constant and independent of the stretching temperature and the stress level. The end of the secondary creep as well as the creep failure time is reached once the deformation of the crystalline skeleton increases to the limit. It shows an Arrhenius behavior between the creep failure time and temperature, which can be used for predicting the creep failure time at a lower temperature.