Polycyanurates. Innovative structural and functional materials

A review with 12 refs.; polycyanurates are a young but well-developed group of high-temp. thermosetting polymers. Their rapid development during the last decade was primarily stimulated by the emerging requirements in aerospace and microelectronics applications, which cannot be met by common thermosets, e.g. epoxies. Some of the main reasons for the growing acceptance of polycyanurates as innovative structural and functional materials are: approved epoxy technologies can be used for handling and curing of the precursors (cyanate ester resins), no admixing of extra hardener is necessary; because the resin is self-hardening, the processing characteristics can be adjusted with a wide range of common catalysts, and, depending on the type of the backbone structure (cyanate ester monomer), a unique range of properties can be achieved including glass temps. up to 400 .degree.C, high toughness compared to other high-Tg thermosets, low dielec. losses, low inherent flammability, low optical damp ing, high chem. resistance and low corrosion potential. Finally, the range and combination of properties can easily be widened by copolymn. of cyanate esters with a variety of other reactive compds.