Towards a methodology for designing RCP-resistant polyethylenes using batch scale test methods [PE]

 

# 2010 Vancouver

This paper outlines a PE100 design methodology which gives central importance to the separate modelling and measurement of plane-strain and plane-stress dynamic fracture resistance. The former is difficult to measure but can be estimated from weight-average molecular weight; the latter is related to high-rate adiabatic tensile deformation which can be estimated from low-rate tensile test data. An overall dynamic crack resistance is then predicted as a function of temperature and pipe wall thickness. Meanwhile, employing a semi-analytical RCP model, the crack driving force is calculated as a function of temperature, pressure and pipe size. The outcome is an estimate of critical pressure as a function of temperature and, hence, of the critical temperature. The entire scheme is demonstrated using a group of experimental resins in the −20 to +10◦ C transition temperature range. Early results indicate the potential of the scheme for guiding PE100 resin design, while highlighting areas in which better modelling is needed.

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