High-temperature phthalonitrile matrix containing silane fragments

A new low melting highly hydrolytically stable phthalonitrile monomer containing silane fragment was synthesized by a three-step procedure and cured to obtain a highly heatresistant thermoset. The polymer demonstrated the glass transition temperature of 485°C and the decomposition onset temperature over 500°C. Stiffness of the obtained thermoset appeared to be the highest among those of the reported silicon-containing phthalonitrile thermosets.