Is 6PPD an antiozonant based on p phenylenediamine?

6PPD is an organic chemical widely used as stabilising additive (or antidegradant) in rubbers, such as NR, SBR and BR; all of which are common in vehicle tires. Although it is an effective antioxidant it is primarily used because of its excellent antiozonant performance. It is one of several antiozonants based around p -phenylenediamine.

Is 6PPD a sacrificial agent?

Despite 6PPD being used in tires since the mid 1970s, its transformation to quinones was first recognized in 2020. The oxidized products are not effective antiozonants, meaning that 6PPD is a sacrificial agent.

Is 6PPD a toxicity hazard?

However, this same property facilitates the transfer of 6PPD and its oxidation products into the environment as tire-wear debris. The 6PPD-quinone (6PPD-Q, CAS RN: 2754428-18-5) is of particular and increasing concern, due to its toxicity to fish.

How do 6PPD and 6ppd-quinone enter the environment?

6PPD and 6PPD-quinone enter the environment through tire-wear particles and are sufficiently water-soluble to enter river systems via urban runoff. From here they become widely distributed (at decreasing levels) from urban rivers through estuaries, coasts and finally deep-sea areas.