KINETICS OF ETHYLENE POLYMERIZATION AND F ORMATION OF ACTIVE-CENTERS IN HOMOGENEOUS CATALYST SYSTEMS BASED ON ZIRCONIUM COMPOUNDS AND POLYMETHYLALUMOXANE

Today's knowledge of the structure of active centers of catalyst syste ms based on zirconium derivatives and polymethylalumoxane are reviewed , and the kinetics of olefin polymerization with such systems is exami ned. The published data, the data on the kinetics of ethylene polymeri zation obtained in this study, and quantum-chemical calculations were used to derive new concepts describing the formation and structure of a multicomponent active center. To describe the polymerization kinetic s, appropriate mathematical models were developed. These models offer a uniform basis for the explanation of experimental data, for example, transition from one kinetic pattern to another qualitatively differen t kinetic pattern as the concentration of the components is continuous ly varied. They also enable the analysis of potentialities of various methods in measuring the number of active centers and chain propagatio n rate constants.