Frequently Asked Questions — AEM O-Rings
What is AEM ethylene acrylic rubber?
AEM (Ethylene Acrylic Elastomer), sold commercially as Vamac® by DuPont, combines an ethylene backbone with acrylic ester groups. This structure delivers a balance of high-temperature performance, oil resistance, and ozone resistance that exceeds ACM in heat range and exceeds standard NBR in high-temperature durability — filling a gap between conventional elastomers.
What temperature range can AEM o-rings handle?
AEM o-rings operate from −40 °C to +175 °C in hot oil service, with short excursions to +200 °C. This positions AEM above ACM (max +175 °C, but worse cold performance) and significantly above NBR (max +120 °C), while maintaining −40 °C cold flexibility that ACM cannot match.
What chemicals is AEM resistant to?
AEM has good resistance to automatic transmission fluid (ATF), engine and gear oils, hot air, ozone, CO₂, and mild dilute acids. It is not recommended for aromatic or chlorinated solvents, concentrated acids or alkalis, steam, glycol coolants, or brake fluids, where EPDM or FKM would be the correct choice.
What are typical applications for AEM o-rings?
AEM o-rings are used in automotive automatic transmissions and transfer cases, turbocharger hot-side seals, supercharger intercoolers, and high-performance powertrain sealing where ACM's limited cold-temperature performance (−25 °C) is insufficient and the full cost of HNBR is not justified.