Analytical Sciences

Interactions of Anion-Exchange Resins with Polyacrylates in Atmosphere

Hiroya TAUCHI, Yasumoto SAKAI, Noriyuki OKAWA, Hanifa FAOZIA, Genki MIZUGUCHI, Takashi YASUI, Kazutake TAKADA, and Akio YUCHI

Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan

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 CO₃²⁻. Using the slightly acidic condition caused substantially no exchange by CO₃²⁻ 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.

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