para-PhenyleneDiamine (PPD) is a widely used chemical in almost all hair dye formulations.  This compound is also used as a photographic developing agent and as an intermediate in the manufacture of azo dyes, antioxidants, and accelerators for rubber vulcanization.

p-Phenylenediamine is primarily used as a dye intermediate and as a dye.

CAS No of Para Phenylenediamine : 106-50-3 

Acute (short-term) exposure to high levels of p-phenylenediamine may cause severe dermatitis, eye irritation and tearing, asthma, gastritis, renal failure, vertigo, tremors, convulsions, and coma in humans.

This polymer arises from the reaction of PPD and terephthaloyl chloride. The reaction of PPD with phosgene gives the diisocyanate, a precursor to urethane polymers.

p PHENYLENEDIAMINE