Polymerization of acrylonitrile by V⁵⁺–lactic acid system in aqueous sulfuric acid

Abstract

Kinetics of polymerization of acrylonitrile by the redox system V5+–lactic acid in sulfuric acid at 20–35°C was studied. Oxidation of lactic acid by V5+ in the absence of monomer was also carried out under identical conditions. The rates of polymerization, V5+ disappearance and the chainlengths of polyacrylonitrile were measured. From the results it is concluded that the polymerization reaction is initiated by an organic free radical arising from the V5+–lactic acid reaction with termination by V5+ ions. Mutual termination of active polymer radicals does not appear to operate under the conditions studied. The various rate parameters were evaluated.

Polymerization of Acrylamideinitiated by V(v)-Cyclohexanone Redox System in Micellar Phase: A Kinetic Study

“…The availability of the acrylamide at the micellar interfaceis an increase in its concentration, and leads to the rate enhancement. The independence of -R V on monomer concentration was also observed in other redox systems [29,30]. 1.985) obtained from bilogarithmic plot of R P(obs) vs. AM ( Figure 2).…”

Kinetics of polymerization initiated by Mn3+–substrate redox system. I

“…The k,/kt value at 3OoC is 0.27. The k p h t decreases with increase of temperature; a similar observation was made by Santappa et al7 AE values for k , (26.4 K cal), kp/kt (-7.6 K cal), and As'303 K values for k, (18.34 eu) and k p h t(-86.26 eu) were evaluated.…”

Effects of surfactants on acrylonitrile polymerization initiated by a Cr(VI)–cyclohexanone redox system: A kinetic study

“…The important role of surfactants in polymerization has been studied since the early 1940s. [1][2][3][4] A good amount of work has been done on the polymerization of vinyl monomers in the presence of surfactants with various initiators. Friend and Alexander 5 observed that different cationic surfactants reduced the rate of acrylamide polymerization initiated by potassium persulfate.…”

“…They explained it by the assumption that the primary radicals (S 2 O 8 ϭ ) were bound strongly to a positively charged Stern region of the cationic micelles in comparison with the counterion. The permanganate-initiated acrylamide polymerization rate was also reduced in the presence of a cationic surfactant because of the ion-pair binding of MnO 4 Ϫ with a large cation (RN ϩ ), which lowered the rate of formation of primary radicals. 6 Behari and coworkers 7 observed that the anionic surfactant [sodium dodecyl sulfate (SDS)] enhanced the rates, whereas the cationic surfactant [cetyltrimethylammonium bromide (CTAB)] reduced the rates considerably for persulfate-initiated acrylamide polymerization in agreement with the results of Hussain and Gupta.…”