scope:

NEN-ISO 18488 specifies a method for the determination of the strain hardening modulus which is used as a measure for the resistance to slow crack growth of polyethylene. The strain hardening modulus is obtained from stress-strain curves on compression moulded samples. This International Standard describes how such measurement is performed and how the strain hardening modulus shall be determined from such a curve. Details of the required equipment, precision, and sample preparation for the generation of meaningful data are given. This International Standard provides a method that is valid for all types of polyethylene, independent from the manufacturing technology, comonomer, catalyst type, that are used for pipes and fittings applications.