Thermally Conductive, Electrically Non-Conductive Silicone Meets NASA Low Outgassing Specifications

Master Bond MasterSil 323AO-LO is a two component silicone elastomer with a self-priming feature, designed for bonding, sealing and gap filling applications. This electrically insulating and thermally conductive compound meets NASA low outgassing specifications and can be used in the aerospace, electronic, optoelectronic and specialty OEM industries.

This system has a thermal conductivity of 1.15-1.30 W/(m•K). It is highly flexible with a low tensile modulus of 500-700 psi, an elongation of 50-60%, and a hardness of 70-75 Shore A. This combination of properties enables it to withstand aggressive thermal cycling and mechanical shock. MasterSil 323AO-LO has a relatively high strength profile for a silicone with a tensile lap shear strength of 250-350 psi at room temperature. It bonds well to a wide variety of substrates, including metals, composites, glass, ceramics, plastics, and other silicones without imparting residual stress when heat cured. Serviceability is from -65°F to +400°F [-54°C to +204°C].

MasterSil 323AO-LO features a paste-like consistency, which allows it to also be used as a gap filling material where minimum flow after application is desired. This formulation offers a variety of cure schedule options, with the optimum being overnight at room temperature followed by 3-5 hours at 125-175°F. It does not require exposure to air for complete cross-linking. MasterSil 323AO-LO has an easy-to-use 1:1 mix ratio and is available for purchase in standard containers or gun applicator kits making it convenient for manual or automated dispensing.

Master Bond Addition Cured Silicones

MasterSil 323AO-LO is an electrically isolating, thermally conductive silicone that meets NASA low outgassing specifications. This two-component compound is highly flexible and withstands temperatures up to 400°F. Read more about Master Bond’s addition cured silicones at or contact Tech Support. Phone: +1-201-343-8983 Fax: +1-201-343-2132 Email:

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James Brenner
Marketing Manager
Tel: +1-201-343-8983
Fax: +1-201-343-2132

Master Bond Inc.
154 Hobart Street
Hackensack, NJ 07601-3922

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