Thermally Conductive, Electrically Insulative Potting Compound Resists High Temperatures

Master Bond Supreme 121AO is a NASA low outgassing approved epoxy suitable for bonding, sealing and potting applications. Featuring a high glass transition temperature of 200-210°C, it resists temperatures up to 550°F. This system exhibits an element of toughness, and is not as stiff as conventional epoxies that withstand extreme temperatures.

Supreme 121AO has a noteworthy strength profile with a tensile modulus of 750,000 to 850,000 psi at room temperature and a compressive strength of 26,000 to 28,000 psi. Its thermal conductivity is 4-5 BTU•in/(ft²•hr•°F), and it is also electrically non-conductive. Shrinkage upon cure is exceptionally low. This system not only withstands thermal cycling and mechanical stresses, but also resists many chemicals, including water, oils, fuels, acids and bases. Supreme 121AO may be used in aerospace, electronic, opto-electronic and OEM applications.

This two part epoxy has a mix ratio of 100 to 80 by weight. The viscosity of the mixed compound is 10,000-25,000 cps, making it readily pourable for potting and casting. It has a long working life after mixing of 2-3 days, for a 100 gram batch. The recommended cure schedule is 1-2 hours at 200°F followed by 3-4 hours at 250°F, and then 4-6 hours at 300°F. Additional post curing at 350°F for 2-4 hours will further enhance product properties.

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