The state of ion aggregation in ionomers based on copolymers of styrene and acrylic acid - 2. Small-angle X-ray scattering studies

Small-angle X-ray scattering results for ionomers containing alkali metals based on copolymers of styrene-acrylic acid and styrene-methacrylic acid ob tained in emulsion are presented. A study has been conducted on the influen ce of content, the type of salt and the type of alkali metal in styrene-bas ed ionomers on the state of ion aggregation. In all the cases, the state of ion aggregation is dependent on the content of an introduced acrylate or m ethacrylate and the type of the introduced alkali metal. The obtained resul ts indicated that, in the case of ionomers containing cesium acrylate, aggr egates of larger sizes are formed than when containing cesium methacrylate. For all the investigated ionomers, the increase of temperature causes the increase of sizes and number of clusters. These results also indicate that, in the case of ionomers containing lithium and sodium ions at this content of acrylate at room temperature, the scattering maximum is absent. In the case of Potassium and cesium ionomers, the scattering maximum appears, whic h may be attributed to the larger ionic aggregate clusters. For all the inv estigated ionomers, the increase of temperature causes the increase in size s and number of ionic aggregates. (C) 2000 Elsevier Science Ltd. All rights reserved.