Effect of metal ion species on mechanical relaxation of ethylene-co-methacrylic acid based ionomers
Zeng Xiangsheng; Araki Osamu; Takahashi Masaoki; Takigawa Toshikazu; Masuda Toshiro
Abstract:Dynamic viscoelasticity of ethylene-co-methacrylic acid (EMAA) based ionomers containing Zn or Na as well as EMAA was investigated. The film samples used for viscoelasticity measurements were molded at 195 degree. Two kinds of specimens, quenched and slowly cooled samples after molding, were prepared for each polymer specimen. For the quenched samples, the effect of aging on dynamic viscoelasticity was also examined. The temperature dispersion curves of dynamic storage modulus (E') of the ionomers obtained by quenching showed a large decrease around 35 degree due to the glass transition of EMAA ionomers. The ionomers prepared by slow cooling showed a high value of E' in the high temperature region, compared with the quenched samples. This may be due to the difference in the degree of ionic cluster formation in the ionomers. The values of E' at low temperatures increased with aging time for the quenched samples, which originates from the equilibration of the glassy state by aging. Key Words:ionomer, dynamic viscoelasticity, temperature dispersion, metal ion, cooling rate, aging time