Polymerization continued carboxyl groups, effect

These anions are normally not reactive enough to continue propagation and the chains are thus effectively terminated. The peroxy and carboxyl anions usually are finally obtained as HO and HOOC groups when a proton donor is subsequently added to the polymerization system. 

As these anions are not reactive enough to continue propagation, the chains are effectively terminated. By adding a proton donor subsequently to the polymerization system, the peroxy and carboxyl anions are converted to OH and COOH groups. A notable example of the application of the latter reaction is the preparation of carboxyl ion terminated polybutadiene by anionic polymerization of butadiene with bifunctional initiators, followed by termination with CO2 ... 

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