Interactions of Anion-Exchange Resins with Polyacrylates in Atmosphere

The interactions of polyacrylates (PAs with mean molecular weight of 4.5, 25, and 250 kDa; Na⁺,pa^-) with anion exchange resins in the Br^- form (AXRs; -R⁺,Br^-) were studied under practical conditions by reaction stoichiometry and spectroscopy. The stoichiometric or an excess amount of PA(4.5 kDa) completely replaced Br- in the AXRs of the cross-linking degree of 2 or 8%, respectively, to give (-R⁺,pa^-), due to enhancement in selectivity of carboxylate group by multiple interactions. In contrast, PA(250 kDa) exchanged Br^- only on the surface of AXRs and did not penetrate into the resins; CO₂ was involved in the system to induce exchange with CO₃^2-. Using the slightly acidic condition caused substantially no exchange by CO₃^2- but induced coextraction of PA with proton as free Hpa. PA(4.5 kDa) once penetrating into the resin phase as (-R⁺,pa^-) or free Hpa was reversibly eluted under the appropriate conditions.