Advanced Short‐Term Approaches to Estimate the Long‐Term Mechanical Behavior of Polymers at Static Loading Conditions

Abstract

Conventional methods for testing the long‐term resistance against creep and slow crack growth (SCG) become more and more unusable for highly improved polymers due to the required long times of often more than 1 year. Therefore, there is a great need for developing new time‐saving methods for predicting the lifetime of such polymers. In this study, the authors describe one of these methods in more detail. The strain hardening method (SHM) is based on uniaxial tensile testing to estimate the time to failure. It has been shown that the strain hardening modulus can be easily determined using SHM with testing times of only a few hours. Due to the same molecular processes during SHM and conventional methods such as full notch creep test (FNCT) and Pennsylvania edge notch tensile (PENT) test, the strain hardening modulus covers the SCG resistance in pipe‐grade high‐density polyethylenes (PE‐HD) to a high degree.