Potentiometric titration is ideally suited for titrating functional groups in monomers, in particular monomeric mono- and polyacids as well as polyols. Application Bulletin 200 describes the determination of the acid value, hydroxyl value, and isocyanate value by automatic potentiometric titration. The acid and hydroxyl value are determined according to ASTM, the isocyanate value is measured according to ISO.
Titrations of functional groups in monomers, in particular monomeric mono- and polyacids as well as polyols, are mostly carried out in nonaqueous, nonpolar solutions. Hence, they are accompanied by very little potential change, leading to flat and erratic titration curves.