Viscoelastic properties of ethyl acrylate ionomers. I. Stress relaxation

Ethyl acrylate ionomers were studied by stress relaxation. The results are compared with those for the styrene ionomers studied previously. The behaviour of the two systems is qualitatively similar, although significant quantitative differences exist. Specifically, the onset of thermorheological complexity is found here at 12–16 mole% of ions, while in styrene it is observed at ca. 6 mole%. Furthermore, the modulus‐temperature plots show great similarity if the present samples are compared with the styrenes containing about half as many ions. Other properties show similar trends. The increased dielectric constant of the acrylates is believed to be responsible for the observed differences in the two systems. The effect of a change in counterions was also studied to some extent. The onset of thermorheological complexity is seen to be qualitatively related to the size and charge of the cation.