Polyether polyurathane based on 4

4'-diphenylmethane diisocyanate (MDI)

N-methyl di-ethanolamine. (MDEA) and pplytetramethylene oxide (PTMO) were synthesized in the tertiary molar ratio of 2:1:1. As a result of the reaction of the tertiary amine of MDEA with γ-propane Sulfone

a series of zwitterionomers were prepared in different degrees of sulfo-nation. The dielectric properties of these samples were determined in different temperatures ( - 150 to 30℃) and frequencies (20 Hz to 100 kHz)

It was found that as the degree of sul-fonation increases

the real permittivity (ε') is increased and the dielectric loss peak of a-relaxation shifts to lower temperatures indicating as improvement of phase seperation and the activation energy of a-relaxation (Ha) was decreased while thet of β-relaxation (Hβ) was nearly unchanged. The results of the dielectric measurement coincide with the dynamic me-chanical analysis.