Herbert K. Wiese

Determination of Peroxides in Synthetic Rubbers

Abstract Peroxides are found in synthetic rubbers either as the result of attack by oxygen, usually from the air, or as a residue from polymerization operations employing peroxide catalysts. Because of possible detrimental effects of active oxygen on the properties of the rubber, a method of quantitative determination is needed. The concentration of peroxides in substances of lower molecular weight may be determined with ferrous thiocyanate reagent, either titrimetrically as recommended by Yule and Wilson or colorimetrically as by Young, Vogt, and Nieuwland. Unfortunately, many highly polymeric substances are not soluble in the acetone and methanol solutions employed in these procedures. This is also the case with hydrocarbon monomers, such as butadiene, containing appreciable concentrations of soluble high molecular weight polymers. Bolland, Sundralingam, Sutton and Tristram recommended benzene as a solvent for natural rubber samples and the reagent made up in methanol. However, most synthetic rubbers ar...