Ionomers

Abstract

Polymers containing ions can be classified into two major families: polyelectrolytes and ionomers. For polyelectrolytes, the ion content is very high, eg, every repeat unit of the polymer has pendent ionic groups. Thus, polyelectrolytes are water soluble. Ionomers are used to define the thermoplastic polymers, which contain a small amount of ionic groups in a matrix of low dielectric constants. Characterization of ionomers is discussed. The use of scattering and X‐ray absorption studies, electron microscopic studies, atomic force microscopy is discussed as ways to determine ionic aggregates and morphology of ionomers. Glass transitions are also studied in this category. Properties of styrene ionomers, as well as polyethylene and polytetrafluroethylene ionomers and ionomer blends are detailed. External polasticizers for ionomers can be used as additives to plasticize either polar or nonpolar regions, or both, depending on the polarities of the additives and the ionomer. Important applications of ionomers include membranes, molded materials, and as fertilizer coatings.