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The Influence of Local Ageing in Brittle Failure of Thermoplastics Pipes

 

Posters - Additional Information

Plastic Pipes Conference Association # 2001 Munich

Pinter, Lang

In this work the influence of three different stabiliser systems on the stress rupture behaviour of high density polyethylene (PE-HD) pipes under constant internal pressure was examined at 60 and 80 °C with special consideration of the quasi-brittle failure by growth of a single crack in the failure regime preceding the global chemical degradation of the pipes. As rheological and thermo-analytical measurements could prove that the pipes of the three formulations did not show global molecular and morphological differences in this regime and that the stabilisation was also still intact, the differences observed for the three formulations are believed to be a result of local ageing around the crack tip related to the combined influence of time, the elevated temperature, the presence of oxygen and water, and the high mechanical stresses in the immediate crack tip region.

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