STRUCTURE AND PROPERTIES OF IONOMERS BASED ON ETHYLENE-CO-METHACRYLIC ACID COPOLYMER (EMAA)

Effects of Ion Aggregates

Abstract

Fourier-transform infrared spectra (FTIR) measurement was made on zinc and sodium ionomers (EMAA-Zn and EMAA-Na) of ethylene-co-methacrylic acid copolymer. It was found that the asymmetry stretching vibration peak of C-O bond of COO^- group in ion aggregates of EMAA-Na appeared at lower wavenumber, compared with EMAA-Zn. This means that complete and stable ion aggregates exist in EMAA-Na. Differential scanning calorimetry (DSC) measurement showed that endotherm peak (T₁) in lower temperature range resulted from melting of subcrystallites of crystalline ethylene in EMAA and EMAA ionomers. Tensile properties and dynamic viscoelasticity of EMAA greatly changed with the introduction of ionic groups.