Master Bond Polymer System U857 is a newly developed modified multifunctional cyanate ester resin system for high temperature service at temperatures up to 750°F! It is a high viscosity, 100% reactive liquid which cures to a heat stable thermosetting polymer by the application of heat. The cured polymer features remarkably high physical strength properties as well as resistance to flames with very little smoke generation. It is capable of sustained service in the 600-750°F range and for limited service as high as 800-850°F. Additionally the heat cure polymer exhibits such desirable performance characteristics as outstanding environmental, chemical and radiation resistance and superior electrical insulation properties. The absence of volatiles greatly enhances processing ease. Typical physical properties of the Master Bond Polymer System U857 as supplied are summarized in Table #1.