Cocatalysts physical properties

In general the MW distribution is adjusted by the choice of (a) catalyst type, (b) activation temperature, (c) cocatalyst type, and (d) cocatalyst amount. Market goals often conflict with PE production goals, and, at the molder s facility, the best polymer physical properties often conflict with the best molding performance. Consequently, most polymer grades represent compromises between these competing demands. 

Metallocene catalysts, for example dicyclopentadienyl zirconium dichloride, in combination with the cocatalyst methylalumoxane, helped establish a regulated set of properties, making it possible to customize molar mass, molar mass distribution, tacticity, heat resistance, rigidity, hardness, cold impact strength, and transparency. Added to these advantageous physical properties is the reactivity of this catalyst... 

Direct evidence for the formation of radical o-quinone (and sometimes p-qui-none) complexes was established in the studies quoted above. Various synthetic techniques starting from elemental metals, nonmetals, metal salts, and complexes have been developed for obtaining these coordination compounds. The peculiarities of their thin structure and physical-chemical properties were investigated. The obtained products have practical applications, in particular for medical purposes. Quinone-based metal complexes have a potential applicability as cocatalysts in a wide range of reactions involving electron exchange between substrate and catalysts. Further studies in this field and on mechanisms of electron mobility between the metal center and the o-quinone ligands are still necessary to understand the vast and complex redox chemistry of these compounds. 

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