Metallocene catalysts for production of block polymers

Simple metallocenes like Cp2ZrCl2 will in copolymerization produce polymers with a statistical comonomer distribution. It has previously been shown that special metallocene catalysts can make copolymers with other microstructures, especially copolymers th at contains alternating blocks of homopolymer and copolymer. Such microstructures are possible to obtain by using unbridged metallocenes where one of the h5 ligands can rotate and thus transforming a rac configuration into a meso. Similar dynamic behaviou r can lead to stereoblock homopolymers of a-olefins. In the resent project we will study a number of metallocenes in polymerisations and copolymerizations in order to make block polymers. The microstructure of the polymers will be characterised, and the m echanism for the formation of block polymers will be studied by theoretical modelling.