High-Performance Thermoset–Thermoset Polymer Blends: A Review of the Chemistry of Cyanate Ester–Bismaleimide Blends

Various blends of a commercial bismaleimide (BMI) mixture, a cyanate ester (CE) and a co-monomer with allyl and cyanate pendant groups were formulated and cured. Differential scanning calorimetry (DSC) data were used to monitor the cure of neat resins, while dynamic mechanical thermal analysis (DMTA) was used to assess cure by the measurement of glass transition temperatures ( T g ). It is suggested that following cyclotrimerization of the CE component, the co-reaction between allyl CE and BMI occurs via an ‘ene’/Diels–Alder mechanism (to form linked interpenetrating networks, LIPNs) as evidenced by 13 C nuclear magnetic resonance (NMR) spectroscopy. DMTA reveals that, unlike the commercial CE/BMI blends, the cured LIPNs may display a single T g value which may exceed 350°C depending on the co-monomers used.