Polyacrylic acid (PAA) was functionalized with a hydroquinone/catechol under the reaction conditions of Minisci. Optimum conditions for maximum functionalization (degree of substitution of 35%) were achieved under the following conditions: [benzoquinone]/[PAA] = 1; reaction time, 6 h; temperature, 75 degreesC nitrogen atmosphere. Redox properties of hydroquinone/catechol-modified PAA (PAA-HQ) were evaluated by their mid-potentials potentiometrically estimated to be 863 mV at 20 degreesC. At 35 degreesC, two-stage oxidation was observed with a mid-potential of 930 mV. These mid-potentials were found to be higher than those of hydroquinone, catechol, and a 1:1 hydroquinone-catechol mixture under the same conditions of potentiometric titration. Under the modification reaction conditions, the modified PAA underwent severe degradation. (C) 2004 Elsevier B.V. All rights reserved.