Relation between life time, failure stress and craze microstructure in polyethylene as evidenced by fracture surface texture analysis after an accelerated Full-Notch Creep Test

A set of five polyethylenes, of which four have 1-butene as co-monomer and one has 1-hexene as co-monomer was evaluated to determine their respective strain hardening values at 80 °C and to determine their failure times applying an accelerated Full-Notch Creep Test at 90 °C with loads varying between 1 and 6 MPa using Lauramine Oxide as detergent in an aqueous solution. The resulting failure times, fracture surface analysis and strain hardening values were described using the Kramer-Berger theory for craze propagation and the Paris-Erdogan phenomenological description of crack growth. From this exercise it is clearly demonstrated that the experimental findings are in line with the Kramer-Berger model. Hence, the viability and validity of these tests for probing the slow crack growth performance of polyethylene grades was shown.