Investigations Electrochimiques des Systemes Redox: Fe3+, Fe(lll)-Complexe, Cu2+, Cu(ll)-Complexe - meta-Bisulfite de Sodium, Initiateurs de Polymerisation de l\u27 Acrylamide en Milieu Aqueux

Plusieurs systemes redox du type: Fe3+, Fe(III)-complexe, Cu2+, Cu(II)-complexe - meta-bisulfite de sodium (Na2S20 5), ont ete etudies, potentiometriquement et potentiodynamiquement en vue de la possibilite d\u27initier la polymerisation de l\u27acrylamide dans un milieu aqueux. A titre de complexant (reactifs de complexation), a ete utilise un ensemble d\u27amines carboxyles avec un groupe iminodiacetique comme element principal, et on a pu constater !\u27influence de !\u27introduction de substituants nouveaux et surtout de nouveaux groupes iminodiacetiques, ainsi que !\u27influence de certaines particularites dans la structure ou de facteurs steriques sur la capacite des complexants a produire des complexes, et sur la stabilite des complexes ainsi formes. Dans toutes ces recherches on a remarque une dependance, en general reguliere et clairement manifestee, de la stabilite des complexes. Les methodes electrochimiques susmentionnees et !\u27electrolyse a potentiel contr6le ont permis de proposer le mecanisme reactionnel le plus probable dans les systemes initiateurs. Several redox systems of the type: Fe3+, Fe(III)-complex, Cu"+, Cu(II)-complex - Na2S20 5, were studied using p0tentiodynamic and potentiometric techniques, in order to evaluate their potential to initiate acrylamide polymerisation in aqueous media. A group of carboxylate amines, with the iminodiacetate group as a basic structural unit, were used as complexing agents in order to follow the effect of the increased coordination ability resulting from the new substituents involved, especially the new iminodiacetate groups. In addition the effects of structural and steric factors on the ability of an agent to form complexes and on the strength of the resulting complexes were examined. In all cases a clear effect of the complex strength factor was found; electrolysis at controlled potential and electrochemical methods allow the most probable reaction mechanism of the initiator systems to be proposed

¹³C NMR analysis of polyacrylonitrile synthesized with manganese ( III ) diacetylaconate rhodanide as initiators

Configurational analyses of polyacrylonitrile polymerized with manganese(III) diacetylacetonate rhodanide at higher temperature have been made. The Bernoullian probability for meso addition on the monomer units in the polymer chain is 0.5237 from methine and 0.539, from nitrile 13C atoms, and the corresponding average number lengths of the meso sequences are 2.196 and 2.1. The results are similar to those for polymers produced in a free radical process. They show that polymers are atactic and that the mecanism of polymerisation, under these conditions, is radical

¹³C NMR analysis of polyvinyl chloride synthesisized with manganese ( III ) diacetylacetone rhodanide as initiators

Configurational analysis was made of polyvinyl chloride(PVC) synthesized with manganese(III) diacetylacetonate rhodanide initiated polymerization. The Bernoullian probability for meso addition on the monomer units were found to be 0.434 from methine and 0.450,calculated from methylene 13C atoms. The results suggested radical polymerization mechanism