Advances in the polymerization of polyolefins with coordination catalysts

Abstract

A historical survey about the development of Ziegler-Natta catalysts for polymerization of propylene is given. After having employed catalysts based on titaniumtrichloride for several years, in the 70's catalysts of the so-called second generation were introduced, which are more effective and yield products of higher crystallinity. Catalysts of the so-called third generation and their morphological properties are extensively dealt with. These catalysts give high yields and highly stereoregular polymers and enable simplification of polypropylene technology and energy saving. In the future polypropylene manufacturing will probably consist only of the polymerization steps with no need for centrifuging, extruding or another post-treatment. ZUSAMMENFASSUNG:Es wird ein historischer uberblick der Entwicklung von Ziegler-Natta-Katalysato

Effects of MgCl2 Crystallographic Structure on Active Centre Formation in Immobilized Single‐Centre and Ziegler–Natta Catalysts for Ethylene Polymerization

“…[1] X-ray diffraction studies have played an important role in characterizing the degree of 'activation' of MgCl 2 supports, which in the early development of Ziegler-Natta catalysts were prepared by ball milling. This transforms a-MgCl 2 into the active d form of MgCl 2 , in which the stacking sequence no longer corresponds to a cubic close packed structure, but is disordered due to translation and rotation The ability of a MgCl 2 support to activate a transition metal catalyst has been found to depend both on the crystallographic structure of the support and on the nature of the catalyst.…”

The Role of CaO in the Ziegler–Natta Catalyst for Propylene Polymerization

“…The use of spherical MgCl 2 adducts as the catalyst support gives rise to the activity and also controls polymer morphology via a replica phenomenon [2][3][4]. Increase in stereospecificity is achieved by introducing an electron donor such as monoester, diester and diether compounds to the catalyst [5].…”

Advantages of an Emulsion‐Produced Ziegler‐Natta Catalyst Over a Conventional Ziegler‐Natta Catalyst

“…A large number of syntheses of Ziegler‐Natta catalysts have been proposed in the literature. For example, supporting Ziegler‐Natta catalyst systems on MgCl 2 has greatly improved their catalytic activity and stereo‐specificity 1–3. Also, catalysts supported on spherical MgCl 2 adducts are usually used to produce spherical polymer particles 4,5.…”