The Effects of Metal Cation Types on Zero Shear Viscosities for Ethylene-co-Methacrylic Ionomer Melts

Abstract

The effects of ion aggregates on zero shear viscosities η 0 for ethylene-co-methacrylic ionomer melts were investigated. Rapid increasing of η 0 for Zn ionomers was shown in high neutralization degree, however, the rapid increase was not observed in all range of neutralization degree for Na ionomers. These results indicate that the formation of ion aggregates strongly affects η 0 only for Zn ionomers. We expect that acid cation exchange, in the case of Na ionomers, cancels effect of ion aggregates on η 0 . On the other hand, formation of ion aggregates affects on damping functions for both cases of Na and Zn ionomers. In the case of Zn ionomers, the value of η 0 in high neutralization degree(>40%) deviated from linear regime. This neutralization degree well corresponds to the onset of strong strain dependence of h(γ). We hence consider that measurement of neutralization dependence of η 0 is one of the ways to detect existence of ion aggregates in EMAA-Zn ionomer melts.

Effect of Blended Ionomers on the Strain Hardening of Polyester-Type Elastomer/Ionomer Blends

“…It should be noted that this apparent increasing of viscosity (linear and non-linear region) was observed when high ND(>40%) ionomer was blended with TPEE. The critical value of ND 40% corresponds to the critical value for the formation for ion aggregates as reported by Nishioka et al 8 It is considered that modification by blending with an ionomer is strongly correlated to the formation of ion aggregates in the EMAA-Na ionomer blend. In Figure 2, the solid line indicates the three times value of linear viscosity, 3 s as mentioned above.…”

“…Therefore, for the case of the TPEE/EMAA-Na ionomer blends, the strain hardening appeared above 40%, which corresponds to critical ND for the formation of ion aggregates. 8 Vanhoorne and Register reported that ion hopping time () of EMAA-Na ionomer is below 100 ms from dynamic rheological measurement. 15 The ion hopping time () means time of reversible equilibrium of bond and dissociation.…”

“…8 These results indicate that there is a critical ND for the formation of ion aggregates that exists between 35-40%.…”

“…6,7 Nishioka et al reported a rheological investigation for the EMAA-Na ionomer in the melt state that showed ionic aggregates are formed at a ND of approximately 40%. 8 These results indicate that there is a critical ND for the formation of ion aggregates that exists between 35-40%.…”

“…[8][9][10][11][12][13][14][15] We consider that research of ionomers for the modification of melt rheology should be noted for new applications. To clarify the roll of blended ionomers for the modification of melt rheological properties, especially uniaxial elongational viscosity, is an important field of research for industrial application.…”