Elastomer Service Life Prediction in Organic Acid Coolants

The objective of this test program was to review the potential physical and chemical changes of four candidate elastomers in engine coolant service. The glycol-carboxylic acid inhibitor technology coolant was selected due to its frequent use and appearance of being more environmentally acceptable as compared to currently used inorganic inhibitors. Within the limits of the test program, we reviewed physical aging using o-ring seals (ASTM D1414) and compressive stress relaxation. The chemical changes were monitored by reviewing surface changes (Fourier Transform Infrared Spectroscopy, FTIR) using attenuated total reflectance (ATR) and dynamic mechanical and rheological testing/thermal analysis, DMRT, which should reflect bulk property changes due to chemical attack.