Importance of the diamine reactant in the production of polyphosphonamides by the interfacial technique

The stirred interfacial polycondensation of phenylphosphonic dichloride and 1,6-hexanediamine has been studied as a function of several reaction variables. The reaction is rapid, being completed in less than 1 min. When organic solvent is varied and reactant molar ratio is varied with an excess of the acid chloride, yield is constant. When reactant molar ratio is varied polymer yield increases with increase in amine concentration. When reactant concentration is increased yield increases. With the addition of a soluble salt in the aqueous phase yield is increased. The above indicates that the diffusion of the amine to the reaction zone is of primary importance in determining polymerization rate and that the diffusion of the acid chloride is relatively unimportant. Polymer yield was found to be dependent on the pH of the amine in the aqueous phase. The observed trend is related to the apparent solubility of the amine in the aqueous phase such that the greater the apparent solubility of the amine, the less the polymer yield. Polymer molecular weight is found to be independent of reaction variables tested. Polymer was also formed from the condensation of phenylphosphonic dichloride with p-phenylenediamine, H₂N-D-NH₂ (where D is a 36-carbon hydrocarbon chain), 1,3-di-4-piperidylpropane, and 4-aminomethylpiperidine; phenyl phosphorodichloridate with 1,6-hexanediamine; chloromethyl phosphonic dichloride with 1,6-hexanediamine.