POTENTIOMETRIC DETERMINATION OF ACID GROUPS IN ACRYLIC POLYMERS AND FIBERS

A procedure is described whereby acidic groups in acrylics at the microequivalents level may be measured by nonaqueous potentiometry. A purified ethylene carbonate-propylene carbonate mixture is used as solvent. Tetramethylammonium hydroxide in this solvent provides a superior titrant. Use of platinum electrodes permits titration of acid groups in polymers in the presence of sodium and potassium salts, thus avoiding the problem of alkali metal poisoning encountered with glass-calomel electrodes. Titration of acid groups present as salts is performed after ion exchange treatment with appropriate resins. The technique is sufficiently sensitive to permit differentiation of acid groups of different strengths in the same polymer sample. Typical titration curves are given. © 1968, American Chemical Society. All rights reserved.