Neue Katalysatoren fuer ein umweltschonendes Verfahren zur loesungsmittelfreien Herstellung von Synthese-Kautschuk. Teilprojekt: Untersuchungen zur Klaerung von Struktur-Wirkungs-Prinzipien fuer den Polymerbildungsprozess durch Polymercharakterisierung Abschlussbericht

The activity of the catalysts and the mechanism of formation of microstructure is preferred investigated in the complex-catalyzed butadiene polymerization. The regulation mechanism of formation of molecular weight is up to this time generally unknown. The essential aim of the part 'polymercharacterization' in the overall project: new catalysts for an environmentally procedure in the solvent free production of synthetic rubber was an analysis of relationships between the catalyst complex as well as carrying out of reaction and the formed molecular weight distribution and their averages. SEC combined with detectors, which are sensitive to molecular weight like light scattering and viscosity, was the analytical method for determination of absolute molecular weight distributions. The formed molecular weight distributions depend on the catalyst themselves, furthermore on the cocatalyst and on the immobilization of the catalyst system on a SiO_2-support. With the kinetic well-grounded approach that Nd-catalysts produce living polymers these correlations are discussed based on equilibria in the catalyst complex. By a specific exertion of influence on the equilibrium of the active species in the catalyst complex changes are shown in the molecular weight distributions in the special case of homogeneous polymerization with a C_1_2-allyl nickel(II) complex. It is possible to predict these changes by using a simulation program developed for treatment of kinetic equations in models of polyreactions. These calculated molecular weight distributions correspond to those which we are measured. (orig.)SIGLEAvailable from TIB Hannover: F98B432 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman