Determination of hydroxyl groups in epoxy resins by potentiometric titration using a reaction with maleic anhydride

A reaction of maleic anhydride with epoxy-dian resins in methyl ethyl keten e was investigated. It was shown by potentiometric titration that the resul ting maleic esters are stable to hydrolysis in acid and weakly acid organic solutions. This reaction can be used for the quantitative determination of hydroxyl groups in epoxy resins. Epoxy groups do not interfere with the fo rmation of maleic esters under the conditions of determination. The optimal reaction conditions were found. The reaction kinetic was investigated, the reaction rate constants were determined at various temperatures, and the a ctivation energy was found. The value of the activation energy indicates th at the reaction is characterized by a low potential barrier.