There are increasing demands on the performance of many elastomeric components used in the automotive industry. These arise from the requirements of longer component lifetime, enhanced levels of performance, and increasing continuous operating temperatures in the engine compartment. The engine mount is a critical application where these trends have created major difficulties for the materials
engineer. Natural rubber, historically the elastomer of choice, may be unsurpassed in dynamic properties, strength, and fatigue resistance but it is approaching the endurance limit with regard to higher continuous operating temperatures. Of the possible replacement elastomers, EPDM, with an appropriately designed molecular structure, is the best solution. After heat aging at 120°C EPDM has better dynamic performance and tensile strength than NR compounds similarly aged. The effects of the EPDM molecular structure, cure system, and compounding on the dynamic performance and the other requirements of the engine mount application are discussed.