Long-term stress relaxation prediction for elastomers using the time-temperature superposition method

Increasingly, manufacturers need to provide warranties of over 10 years on rubber seals, gaskets and air-springs and warranties of between 20 and 30 years on O-rings for underground applications [Parker Hannifin Corp. Compression set vs. compression stress relaxation. vol. 1, No. 3; 2003.]. In order to expedite the development process, experimental concepts for accelerated forecasts of long-term relaxation are required. Previously the standard procedures have relied upon semi-quantitative methods which considered material behaviour at elevated temperatures. The objective of the work presented here is to develop precise forecasting procedures with the use of the time-temperature superposition principle, the Williams-Landel-Ferry (WLF) equation [J.D. Ferry. Viscoelastic properties of elastomers. 3rd ed.; 1980.] and the Arrhenius equation [ISO 11346. Rubber, vulcanised or thermoplastic - estimation of life-time and maximum temperature of use from an Arrhenius plot. 1997.]. (c) 2006 Elsevier Ltd. All rights reserved.