Ionic polymerization under an electric field. Part 15.—Anionic polymerization of styrene in tetrahydropyran

Abstract

“Living” anionic polymerizations of lithium, sodium, potassium, and caesium salts of polystyryl anions were investigated in tetrahydropyran at 25°C in the presence and absence of an electric field. The field increased the k″pK½ term, except for the caesium salt; k″p is the free ion rate constant and K the dissociation constant of ion pairs. From the conductivity data, the field effect was concluded to be due to an increase in k″p with increase of the field. For the sodium and potassium salts, k″p reached a limiting value (≈ 1.2 × 105 M–1 s–1) above 3kV/cm, which was attributed to desolvated free ions. The ion-pair rate constants were 10, 13, 61 and 64 for lithium, sodium, potassium and caesium salts, respectively, and were not influenced by the electric field. The small k″p values of the lithium salt in the absence of the field and its large field effect are discussed.