Abstract: Four different ionomers containing--SO^-₃(19940936-1399-1.jpg)H_4-xEt_x ionic groups were prepared by neutralizing the sulfonated EPDM with ammonium hydroxide, ethylamine, diethylamine and triethylamine respectively.The elemental analysis, stress-strain, dielectric properties and density measurement data showed that the neutralization degree, tensile strength, temperature of β′relaxation peaks and the density of the ionomers all decreased with the increase of the ethyl group numbers(x)in different amines, which were utilized as a neutralizing agent.When x=0, relaxation peak splited into two relaxation peaks αand β, which indicated that the ionic groups(-SO₃NH₄)in the ionomers aggregated into compact ion clusters, and resulted in two phases morphology.However, in the case of x>1 and the precursor S-EPDM-H, the homogeneous phase morphology system was still maintained because the ionic groups only gathered into multiplets. As the number x increased, the volume of the ion pair increased and the positive charge of the nitrogen atoms decreased, hence the cohesionenergy of the ion pairs, as well as the rigidity of the multiplet and the densities of the samples decreased.

Key words: Sulfonated ethylene-propylene-triatomic rubber(S-EPDM-H), Ionomer, Dielectric property