SULFONATED POLYSTYRENE IONOMERS NEUTRALIZED BY BIFUNCTIONAL AND MULTIFUNCTIONAL ORGANIC CATIONS .1. AN INFRARED SPECTROSCOPIC STUDY

An infrared spectroscopic investigation of lightly sulfonated polystyrene blended with ten different organic small molecules containing hi-, tri-, and quadrifunctional amine or pyridine groups was undertaken. Proton transfer from the sulfonic acid moieties of the polymer to the nitrogen functions of the small molecules, giving rise to ion pairs and hence ionic cross-linking, was clearly detected. The extent of proton transfer was correlated qualitatively with the relative basicity of the small molecule. A quantitative calculation of the degree of proton transfer was performed, based primarily on the normalized area of the absorption band and shoulder at 900-906 cm(-1). The results range from about 50% proton transfer or less to purine, 2,2'-pyridil, and N-phenyl-1,4-phenylenediamine to almost complete proton transfer to 1,6-hexanediamine and 1,4-phenylenediamine.