Stability Constants of Some Complexes of t-Butyl Mesityl Nitroxide

Abstract

Stability constants for complex formation of t-butyl mesityl nitroxide with various solvents and monomers have been determined in the range 25-85 C by gas-liquid chromatography and a spectrophotometric method. In general, molecules with extensive conjugation form the most stable complexes but diethyl malonate provides a notable exception. Solvents which form the most stable complexes show the strongest effects on the rate coefficients of propagation in radical polymerization of methyl methacrylate and styrene. This correlation supports the view that a proportion of the active macroradicals are complexed with monomer or solvent.