Thermally stable phthalonitrile matrixes containing siloxane fragments

New low-melting phthalonitrile monomers suitable for the production of high-temperature matrixes for polymer composite materials are synthesized. After the introduction of siloxane bridges into a monomer, the glass-transition temperature decreases to–1–27°С, depending on the type of substituent at the silicon atom. These compounds are found to be sufficiently hydrolytically stable, despite the presence of sensitive siloxane bonds. The cured resin retain properties featured to the class of phthalonitriles, such as a high onset tеmperature of degradation (>530°С in argon), a high heat deflection temperature (>420°С), and char yield. The considered compounds make it possible to widen the temperature window for processing of phthalonitrile resins without any change in the properties of the final material.