Potentiometric Titrations of Polyacrylic Acid and Polymethacrylic Acid Samples Obtained by Polymerization in Bulk or Organic Solvents with Radical Initiators

Abstract

Acrylic acid was polymerized in bulk or solvents of low polarity such as benzene at relatively high temperature with radical initiators. Potentiometric titrations of aqueous solutions of the polymers were carried out using NaOH, (n-Butyl) ₄NOH and Ba (OH) ₂. These polymers showed somewhat higher pK-values than those of polyacrylic acid samples obtained by polymerization in water or derived from usual polymethyl acrylate, indicating that they have a more isotactic structure. On the other hand, the potentiometric titration behaviors of polymethacrylic acid samples obtained by radical polymerization were practically independent of the nature of solvents used for the polymerization. Some discussions were given for the results.