Many polymer chemists are concerned with limiting the rate of disproportionation during polymerization. Although disproportionation results in formation of one new double bond which may react with the polymer chain, a saturated hydrocarbon is also formed, and thus the chain reaction does not readily proceed. During living free radical polymerization, termination pathways for a growing polymer chain are removed. This can be achieved through several methods, one of which is reversible termination with stable radicals. Nitroxide radicals and other stable radicals reduce recombination and disproportionation rates and control the concentration of polymeric radicals.