Synthesis and properties of a bisphenol A based phthalonitrile resin

A multiple aromatic ether linked phthalonitrile was synthesized and characterized. The oligomeric phthalonitrile monomer was prepared from the reaction of an excess amount of bisphenol A with 4,4-difluorobenzophenone in the presence of K2CO3 as the base in an N,N-dimethylformamide/toluene solvent mixture, followed by end capping with 4-nitrophthalonitrile in a two-step, one-pot reaction. The monomer properties were compared to those of the known resin 2,2-bis[4-(3,4-dicyanophenoxy)phenyl]propane after being cured in the presence of bis[4-(4-aminophenoxy)phenyl]sulfone. Rheometric measurements and thermogravimetric analysis showed that the oligomeric phthalonitrile resin maintained good structural integrity upon heating to elevated temperatures and exhibited excellent thermal properties along with long-term oxidative stability. The ether-linked phthalonitrile resin absorbed less than 2.5% water by weight after exposure to an aqueous environment for extended periods. (c) 2005 Wiley Periodicals, Inc.