For the characterization and comparison of polyethylene grades used for the manufacture of packagings and Intermediate Bulk Container (IBC) the following parameters are required: melt flow rate (MFR), density (D), low temperature notched impact strength (NIS), Full Notch Creep Test (FNCT) and increase of MFR by molecular degradation (Ox). The correlation of these material parameters determined on the basis of specimens prepared from compression moulded sheets of polyethylene grades and the test behavior of packagings has been investigated in several tests.

The environmental stress crack resistance determined by Full Notch Creep Test (FNCT) represents the impacts from the stacking tests at 40 °C performed with standard liquid wetting solution (without pre-storage) and with normal butyl acetate saturated wetting solution (pre-storage with normal butyl acetate). The molecular degradation by the determination of MFR increase represents the impacts from the drop test and stacking tests performed after pre-storage (21 and 42 days at 40 °C) with standard liquid 55 % nitric acid.

The low temperature impact strength represents the impacts from the drop test at -18 °C performed without pre-storage and after pre-storage with standard liquid 55 % nitric acid. A good correlation was found between the test results and the material parameters.

Subject
Test methods, Materials, Degradation, Packaging, Wetting, Chemical resistance, Density, Cracking resistance, Liquids, Stress, Nitric acid, High density polyethylene, Test specimen
Keywords:
dangerous goods packagings, HDPE grades, material parameters, design type tests
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2009
Association for Materials Protection and Performance (AMPP)
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