Thermal and mechanical evaluation of cyanate ester composites with low-temperature processability

A low viscosity bisphenol E cyanate ester monomer was used as a reactive diluent in a bisphenol A/novolac cyanate ester to achieve a low viscosity prepolymer with a viscosity suitable for processing at room temperature. Dynamic mechanical analysis was conducted on carbon fiber composite specimens manufactured from two cyanate ester blends with varying catalyst compositions. It was shown that post-curing was needed to produce a polymer matrix with a single glass transition relaxation, but increases in post-cure temperature above 204 °C resulted in slight reductions in Tg and modulus. Also, increasing catalyst composition was shown to have a negative effect on Tg.