Synthesis and characterization of triphenylphosphine oxide containing monomers and high performance polymeric materials

Abstract

Novel functionalized triphenylphosphine oxide containing monomeric materials were prepared and subsequently incorporated into high performance aromatic polyimides, polyamides, copolysiloxane-poly(aryl-imide) randomly segmented copolymers, and epoxy network systems. These uniquely designed monomers were prepared via both Friedel-Crafts and Grignard techniques. In particular, two arylene ether diamines, bis[4-(maminophenoxy)phenyl]phenylphosphine oxide (m-BAPPO) and bis[4-(paminophenoxy)pheny] |phenylphosphine oxide (p-BAPPO) were prepared via the nucleophilic aromatic substitution of aminophenoxides onto the activated dihalide bis(4- fluorophenyl)phenylphosphine oxide (BFPPO) in polar aprotic solvents. It was also shown that the reaction of phenylphosphonothioic dichloride with biphenyl or diphenyl ether in the presence of aluminum chloride is a viable method for preparing regiospecific triphenylphosphine oxide derivatives. These derivatives were oxidized, nitrated and reduced to afford isomeric triphenylphosphine oxide containing diamines. Moreover, a sequential addition procedure with thiophosphoryl chloride, fluorobenzene, and benzene with aluminum chloride was investigated for the preparation of the highly desired, activated dihalide BFPPO.

The polymers prepared from the novel triphenylphosphine oxide diamines showed many unique features. All linear polymers displayed high glass transition temperatures (T_g) and substantial improvements in solubility. TGA analyses showed excellent thermooxidative stability for all prepared polymers and gave substantial amounts of char at temperatures where other engineering polymers were completely volatized. This char was shown to induce a self extinguishing behavior in the polymers, thus imparting flame retardancy into the polymeric systems.