Amine-Cured Bisphenol-Linked Phthalonitrile Resins

Abstract Neat polymerization of bisphenol-linked phthalonitrile monomers, which contain no active hydrogen atoms, is extremely difficult and requires several days of continuous heating at 260–290°C before a viscosity increase becomes evident. In the presence of a nucleophilic compound such as an organic amine, the cure time and temperature can be greatly reduced. The amine-cured polymers are more thermally stable than their neat cured counterparts. Preliminary results indicate that the amine causes no significant changes in the mechanical properties of the cured polymer. The bisphenol-linked phthalonitrile resins are particularly appealing as matrices for composite formulations due to the projected low material cost, the greatly improved processability, and the nonreactivity of the prepolymer at ambient temperature.