Advances in Cyanate Ester as a Curing Agent for Epoxy Resin, Part I

Abstract

Cyanate ester is recognized as one of the most important high-performance thermosetting materials used in the electrical & electronic and the composite materials fields. In order to understand the overall picture of cyanate ester as a type of epoxy resin curing agent, the chemical structures and the CAS registration numbers are investigated and classified for various types of cyanate esters including commercially available ones. There are no stoichiometric ratios in the curing reaction of epoxy resin and cyanate ester, because the self-polymerization of cyanate ester is included in the several curing reactions between them. Curing- and cured-properties of epoxy resin/cyanate ester systems are reviewed focusing on the composition dependences for a dozen of key properties such as the curing behavior, the glass transition temperature, the tensile & flexural properties, the impact strength, the thermal expansion, the thermal stability, the water absorption, and the dielectric properties. Some comments are also added on the optimal formulations.