ISO 20965:2005

ISO 20965:2005 specifies the general principles of a method for determining the transient extensional viscosity of polymer melts. The procedure details the measurement of polymer melt specimens stretched uniaxially under conditions of constant strain rate and constant temperature.
The method is capable of measuring the transient extensional viscosity of polymer melts at Hencky strain rates typically in the range 0,01 s-1 to 1 s-1, at Hencky strains up to approximately 4 and at temperatures up to approximately 250 °C. It is suitable for measuring transient extensional viscosity values typically in the range from approximately 104 Pa.s to 107 Pa.s.