Electron spin resonance studies of manganese(II) and copper(II) salts of poly(ethylene‐co‐methacrylic acid)s

Abstract

The ionic interaction of poly(ethylene‐co‐methacrylic acid) ionomer neutralized with Mn2+ or Cu2+ was studied by ESR spectroscopy to explore the local structure in the ionic aggregate. ESR spectra of the ethylene ionomer were obtained as functions of degree of neutralization and temperature. The existence of both isolated and aggregated cations in the ionomer was confirmed by ESR. In addition, the formation of a Cu2+−Cu2+ dimer structure similar to the crystal structure of copper acetate monohydrate was found in ethylene ionomer containing the Cu2+. Cation‐cation interactions changed markedly around 70°C with increasing temperature, representing the onset of the motion of cations in the aggregated ionic structure.

Structural Properties of Ionomers

“…This technique is therefore sensitive to the local environment of paramagnetic ions. ESR measurements have been reported for manga nese and copper salts of copolymers of ethylene and methacrylic acid (68). Both isolated and aggregated cations were found, consistent with the presence of both phase dispersed and phase separated ions.…”

Controls exerted by the Aib residue: Helix formation and helix reversal This article is a US Government work and, as such, is in the public domain in the United States of America.

“…Ethylene ionomers are copolymers consisting of methylene sequences as nonpolar segments and a small amount of methacrylic acid or acrylic acid residues as ionic units 1–24. It is well known that the ionic groups are partially or fully neutralized by metal ions such as Zn 2+ , Na + , Ca 2+ , Cu 2+ , or Mn 2+ 1–26.…”

“…Ethylene ionomers are copolymers consisting of methylene sequences as nonpolar segments and a small amount of methacrylic acid or acrylic acid residues as ionic units 1–24. It is well known that the ionic groups are partially or fully neutralized by metal ions such as Zn 2+ , Na + , Ca 2+ , Cu 2+ , or Mn 2+ 1–26. Because information about the structure and dynamics of ethylene ionomers is indispensable to an understanding of their mechanical, thermal, and other important physical properties, many investigations have been performed with differential scanning calorimetry (DSC),2, 3, 8, 10, 11, 13, 14, 17, 18 X‐ray diffractrometry,2–4, 13, 15, 18, 20, 23, 25, 26 Raman spectroscopy,5, 19 infrared (IR) spectroscopy,7, 8, 13, 19, 22, 24 electron spin resonance spectroscopy,12 dynamic mechanical analysis,13, 14, 17 and dielectric relaxation measurements 13, 16…”

Infrared Spectral Studies on Coordination Structure and Oxidation−Degradation for Cobalt(II) Salts of Ethylene−Methacrylic Acid Copolymer and Their Complexes with an Organic Amine

“…When the sample is cooled from a temperature above T i to room temperature, the disordered ionic aggregates very slowly transform into the ordered ionic aggregates, with a long relaxation time of about 40 days. We have demonstrated that the order−disorder transition model qualitatively explains most physical properties, − but the model has not been universally recognized since direct evidence is not obtained. Moreover, a few other models have been proposed for the change at T i , for example, one relates the change at T i to the melting of quasi-crystallites formed during annealing and another to the evaporation of residual water in the ionomers.…”