Inhibitor & Retarder:
1. Inhibitor:
Inhibitor are those chemical substance whose helps to stop/kill polymer chain's growth.
Example: Phenol, Aromatic-amine, Quinone.
2. Retarder:
Retarder are those chemical substance whose helps to decrease the polymer chain's growth.
Example: Di-phenyl methyl-hydrazyl, Tri-phenyl methyl-hydrazyl.