Microstructure Control of Ethene Homopolymers Through Tailored Ni,Pd(II) Catalysts - Late Transition Metal Polymerization Catalysis - page 42

Fig. 2.12 Different architectures of diimine complexes for the polymerization of ethene.

in a 2 L steel autoclave with a strong mechanical stirrer, a prerequisite for achiev-
ing controlled conditions during polymerization reaction (Tab. 2.5).
The polyethenes obtained with Brookhart's catalyst ( 6d ) had a molecular weight of
4 10 6 g mol -1 and showed a branched microstructure resulting in a broad melting
range at around 90 C. NMR measurements indicate about 55 methyl groups per

1000 C-atoms (Fig. 2.13). In contrast, the symmetric terphenyl complex ( 6c ) pro-
duces high molecular weight, crystalline polyethene which exhibits sharp melting
transition at around 130 C. The molecular weights exceed 4.5 10 6 g mol -1 [38].

Fig. 2.13 Comparison of melting points and branching degrees for 6c , d and 9b , c .