Abstract:

ESR spectra and viscosity measurement have been used to study the aggregation behavior of two kinds of sulfonated butyl rubber ionomers. It was found that at low concentration, intramolecular aggregation occurred, resulting in a lower reduced viscosity, and at high concentration, intermolecular aggregation occurred, resulting in a higher reduced viscosity. The degree of aggregation (DA) can be expressed as a function of ionomer concentration by an empirical equation, DA=Aexp(kc2). The constant k related to tendency of aggregation of ionic groups. It was found that the value of k decreased with increasing hexanol content, indicating that the hexanol-solvation of the ionic groups could weaken the tendency of the ionic aggregation.

Key words: Ionomer, Butyl rubber, Reduced viscosity, Degree of aggregation