This document applies to a variety of substituted p-phenylenediamine antidegradants (PPDs) used in the rubber industry. The three general classes of PPDs are dialkyl, alkyl-aryl and diaryl, which are used to impart ozone resistance to rubber.
The following test methods are of greatest significance in assessing the purity of production PPDs, and hence their suitability for use in rubber. They are specified in this document as follows:
determination of purity by gas chromatography (GC);
determination of purity by high-performance liquid chromatography (HPLC);
determination of ash;
determination of volatile matter.