SULFONATED POLYSTYRENE IONOMERS NEUTRALIZED BY BIFUNCTIONAL AND MULTIFUNCTIONAL ORGANIC CATIONS .2. ORIENTATION AND DYNAMIC-MECHANICAL STUDY

A study of the orientation and dynamic mechanical behavior of lightly sulfonated polystyrene ionomers (PS-0.050SSA) neutralized by ten small organic cations, containing bi-, tri-, and quadrifunctional amine and pyridine groups, is presented. From infrared dichroism measurements, it was found that the orientation function, P-2, of these ionomers increases linearly with the degree of proton transfer calculated in the previous paper.(1) This result shows that the magnitude of segmental orientation is proportional to the effective cross-link density in these ionomers, the cross-links arising from the ion pairs that result from the proton transfer process. Dynamic mechanical thermal analysis indicates that the ion pairs aggregate to an extent which depends largely on the degree of ionization. In the ionomers for which high proton transfer was measured, a second, higher temperature transition is apparent, indicating the existence of clusters in these systems. The effect of the cluster phase on the orientation behavior is discussed.