monomers and homologs thereof would be useful for flame retardant strategy and stabilization in polymer systems other than polyesters and polycarbonates the phosphine oxide containing polycarbonates above may be formed by any method conventional in the art examples of methods to prepare phosphine oxide containing polycarbonates include an interfacial process a transesterification process and a bishaloformate process the preferred method of forming the phosphine oxide substituted polycarbonates is interfacially that is in a mixed aqueous organic system which results in recovery of the polycarbonate in the organic phase a carbonate precursor is used in the interfacial reaction and is preferably phosgene when using an interfacial process it is also standard practice to use a catalyst system well known in the synthesis of polycarbonates and copolyestercarbonates suitable catalysts include tertiary amines tertiary amines include aliphatic amines such as triethylamine tri n propylamine diethyl n propylamine and tri n butylamine and highly nucleophilic heterocyclic amines such as 4 dimethylaminopyridine such amines generally contain at least about 6 and preferably about 6 14 carbon atoms the most useful amines are trialkylamines containing no branching on the carbon atoms in the 1 and 2 positions triethylamine is the most preferred a chain terminating agent to control the molecular weight of the polymers is usually present suitable chain termination agents are those commonly employed for polycarbonate formation including monohydroxyaromatic compounds such as phenol p t butylphenyl and p cumylphenol phenol is preferred quantities of chain terminating agents can range.