Test MethodFull notch creep test (FNCT) of PE-HD - Characterization and differentiation of brittle and ductile fracture behavior during environmental stress cracking (ESC)

- PE-HD materials were investigated with respect to ESC/SCG behavior.
- An improved FNCT-device with continuous elongation monitoring is introduced.
- Various liquid media were employed and classified based on their influence on FNCT results.
- Differentiation of brittle/ductile fracture is proposed based on fracture surface analysis by LSM.

The damage mechanisms slow crack growth (SCG) and environmental stress cracking (ESC), relevant for PE-HD materials are characterized based on improved full notch creep testing (FNCT) of two selected typical PE-HD materials for container applications. In this context, a distinction of the failure mechanisms as well as a categorization of involved media is suggested. Employing a novel FNCT device, elongation data were obtained in addition to conventional time-to-failure results of stress-dependent as well as temperature-dependent measurements. Changes in failure behavior, as determined by fracture surface analysis based on light microscopy (LM) and laser scanning microscopy (LSM), are correlated with FNCT results and used to introduce an additional possibility for the identification of brittle/ductile fracture behavior.

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