ASTM D8363-20

5.1Non-isothermal stress relaxation, also known as temperature scanning stress relaxation, performed at a specific heating rate, delivers a set of parameters useful to specify the properties of thermo-plastic elastomers. It can also characterize the deterioration of the cross-linked rubber network in a reasonable testing time of a few hours.

5.2Stress relaxation tests are typically performed as time-dependent experiments at constant strain and temperature. It is known that temperature has a strong influence on the relaxation time of rubber. When evaluating ageing behavior such as deterioration of the network, a reliable test using isothermal stress relaxation requires extremely long testing times, for example, days or weeks depending on the application.

1.1This test method is used to determine the non-isothermal stress relaxation, also known as temperature scanning stress relaxation (TSSR). Stress relaxation is a characteristic behavior of rubber materials.

1.2UnitsThe values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.

1.3This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.