V-50 is a water-soluble azo initiator, is mainly used for the polymerization of water-soluble vinyl monomer.

V-50 produces cation radical by homolytic decomposition reaction, which generates approximate first order reaction rate, and produces no side reaction in aqueous solution. 
compared to other inorganic (persulfate) peroxysulphate and other water-initiator, V-50 can have decomposition reaction smoothly, steadily and controllably, and produce high molecular weight linear polymers.