Cyanate ester resins functional groups

The third resin in the series of high-temperature thermosetting resins is cyanate ester resin or polycyanurates. The use of cyanate ester resin is limited to aerospace and defense application due to their high cost. Aryl cyanate monomer was first synthesised by Grigat and co-workers [191] and commercial production of cyanate ester (CE) resin started in the mid-1980s. CE resins are characterised by two or more cyanate functional groups (-0-C=N-) with an aromatic or cycloaliphatic backbone. 

Despite their many attractive features, the search for further improvements in performance and reduction in cost of cyanate esters is never ending and a large number of studies have been devoted to matrix modification through blends, and co-curing of these systems. Reactions of cyanate esters with a variety of functional groups like amines [169], hydroxyl [34, 66], epoxy [170-172], phenols, etc., have been reported, among which the most studied are reactions with epoxy [173,174]. Epoxy-cyanate blends are common and found in many commercial and patented resin formulations. 

A series of molybdenum-doped materials based on thermosetting cyanate ester and epoxy resins was prepared and tested as catalysts for the epoxidation of cyclohexene, styrene, 1-octene and propylene with tert-butyl hydroperoxide as oxidant Monomers with more than two functional groups yield highly stable catalysts that can be used in several consecutive reactions without any catalyst reconditioning step. Metal leaching strongly depends on the resin as well as the substrate. 

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