Anelastic and Thermal Properties of Ethylene/Acrylic Acid Copolymers Partially Ionized with Transition Metals.

摘要

Ionomers of five 3d series transition metals (Mn, Fe, Co, Ni, and Cu), two Lanthanide series transition metals (Ce, Sm) and the IV and V series metals (Pb, Bi) were prepared by reaction with 25% solids dispersion of poly (ethylene-co-acrylic acid), EAA, in aqueous ammonia. The unreacted copolymer showed two mechanical relaxations, the glass transition at about 5 deg C and a low temperature secondary relaxation at about -140 deg C with 230 +- 10 kJ/mol and 50+-8 kJ/mol apparent activation energies, respectively. Typically three weight percent of the metal nitrate or acetate was reacted with the copolymer dispersion. After precipitation, drying and molding, the ionomers showed three mechanical relaxations. The low temperature gamma -relaxation was quite strong and shifted about 5 deg C higher compared to the EAA copolymer. The beta -relaxation was extremely weak occurring at -62+-5 deg C in the loss tangent at 1.0 Hz. The alpha -relaxation or glass transition for 3 per cent transition metal ionomers occurred at about 26+-3C for +3 oxidation states and Cu sup +2 , but significantly higher for other +2 oxidation states (48 +- 2C for Co, Ni and 35C for Mn) based on G'' maxima at 1.0 Hz and the apparent activation energy was 220+-30kJ/mol. The two group IV and V metal ionomers were much higher loadings and had a much broader and stronger ( beta ') relaxation occurring at -6 +- 4 deg C with 130+-10 kJ/mol activation energies. The lead ionomers were clear but the bismuth ionomer showed macroscopic phase separation. The 3d transition metal ionomers were clear and nicely colored characteristic of their ionization state except for iron which was somewhat cloudy. The Lanthanide ionomers were clear (Ce) or pale yellow (Sm) and also reasonably transparent. (16 refs., 12 figs., 5 tabs.). (ERA citation 13:054327)