Compressive Stress Relaxation (CSR) Testing of Elastomers

This paper presents Compressive Stress Relaxation (CSR) results for various elastomer samples to ascertain their performance in sealing applications. The paper presents results of percent retained sealing force (%RSF) behavior and its relationship with compression set and hardness. Materials studied are used in critical piping and medical seal applications. CSR methodology is used to benchmark various materials in terms of sealing performance. Potential problems with the current standard of testing have also been identified that can affect the resolution and variability of the test. The paper details all the steps involved to perform accurate CSR testing and discusses advantages and disadvantages CSR testing might have over conventional tests used to verify seal performance such as compression set. This is only an introductory study and requires further tests with the same elastomers subjected to other process conditions, such as heat aging are also studied to understand how they affect %RSF. This can also be expanded to other materials to build a database of standard %RSF behavior under identical conditions.