THE OZONATION OF N,N'-DI-NORMAL-OCTYL-PARA-PHENYLENEDIAMINE AND N,N'-DI-(1,1-DIMETHYLETHYL)-PARA-PHENYLENEDIAMINE

Ozone attack on rubber compounds causes characteristic cracking perpendicular to the direction of applied stress. This degradation is caused by reaction of ozone with the double bonds in the rubber molecules. This causes chain scission and the formation of various decomposition products. In this report, the ozonation products of two additional PPDA compounds are described; these are N,N′-di-n-octyl-p-phenylenediamine (DnOPPD) and N,N′-di-(1,1-dimethylethyl)-p-phenylenediamine (DMEPD). The results of this study are consistent with a combined 'scavenger/protective film' mechanism for antiozonant protection of unsaturated rubber.