Para-phenylene-diamines (PPDs) have for decades been indispensable antidegradants for sulfur-crosslinked vulcanizates. Given their hitherto unsurpassed range of effectiveness, compounds such as 6PPD will be irreplaceable even in the long term, despite serious drawbacks. Many attempts have been made to reduce their drawbacks by structural modification, with some degree of success. Novel compounds based on p-phenylenediamine, some of which are graftable, have provided a marked reduction in the undesirable properties of commercial additives without substantial loss of effectiveness. Rubber compounds based upon the use of existing p-pheylene diamines in which problems such as staining, loss of effectiveness (through volatility or extraction of the antidegradant) or migration of additive components injurious to health have limited their end use to specific markets, can now be formulated with a recently discovered, more effective stabilizer.