Table 1 gives the world production data regarding polyolefins and their copolymers as well as those concerning the other main plastics. As may be inferred from such data, the polyethylenes obtained via catalytic processes and polypropylenes (homopolymers and modified products) rank fourth and fifth in terms of quantities produced. Polypropylene fibres and ethylenepropylene based elastomers rank fourth and fifth in their respective classifications.

Catalytic Olefin Polymerization

Catalysis continues to play a vital role in polymerization of such olefins as ethylene and propylene. A voluminous patent and scientific literature describing transition metal catalysts for olefin polymerization has emerged since the original discoveries by Ziegler, Natta, and other workers [1–6], Significant progress in polymerization catalysis has been made in the last 15 years, particularly with the development of methods to increase the efficiency of transition metal catalysts in olefin polymerization. Success in this area has provided the basis of simplified, less costly plant operations which do not require removal of residual catalyst from the polymer [3–9].

Studies with High Activity Catalysts for Olefin Polymerization

1955 berichteten Natta und seine Mitarbeiter vom Istituto di Chimica Industriale del Politecnico di Milano uber die Eigenschaften hochkristallinen Polypropylens und anderer Poly-α-olefine, die zumindest in langeren Abschnitten der Hauptkette uber Kohlenstoffatome der gleichen absoluten Konfiguration verfugen (isotaktische Poly-α-olefine). Die Entdeckung der neuen kristallinen Polymere wurde schon in jener Zeit als „revolutionary in its significance” erkannt und eroffnete eine neue Epoche der Polymerwissenschaft und Polymertechnik. Kristallines isotaktisches Polypropylen fand infolge seines relativ hohen Schmelzpunktes und seiner hervorragenden mechanischen Eigenschaften weite Verbreitung auf vielen Anwendungsgebieten der Kunststoffe. – 25 Jahre nach dieser Veroffentlichung wird ein Uberblick uber die weiteren Entwicklungen bei der stereospezifischen Polymerisation von Propylen gegeben, und es werden die teilweise noch offenen Fragen nach der Struktur der katalytischen Zentren und nach dem Reaktionsmechanismus diskutiert, der die Bildung von praktisch vollstandig stereoregularem Polypropylen bewirkt.

Die stereospezifische Polymerisation von Propylen: Ein Überblick 25 Jahre nach ihrer Entdeckung

A new molecular adduct of MgCl2 with isobutanol, namely MgCl2·4((CH3)2CHCH2OH) (MgiBOH), has been prepared as a precursor to the supporting material for an olefin polymerization catalyst. The MgiBOH adduct and final titanated Ziegler–Natta catalysts have been thoroughly characterized by powder XRD, thermal analysis, Raman spectroscopy and solid-state NMR for structural and spectroscopy aspects. A peak observed at 712 cm−1 in the Raman spectra of MgiBOH indicates the characteristic Mg–O6 breathing mode and the formation of the adduct. The diffraction feature at 2θ = 7.8° (d = 11.223 A) in the XRD confirms the adduct formation and the layered structure. The aim of the present article is to study how the insertion of a bulky isobutanol moiety affects the structural and electronic properties of the MgCl2·isobutanol molecular adduct. Indeed, the focus of the present study is to explore how the presence of isobutanol, in the initial molecular adduct, influences the final Z–N catalyst properties and its activity.

MgCl2·4((CH3)2CHCH2OH): A new molecular adduct for the preparation of TiClx/MgCl2 catalyst for olefin polymerization

The effect of alcohol treatment in the preparation of MgCl2 support by a recrystallization method on the catalytic activity and isotactic index for propylene polymerization

A.N. Roper

Papers

Highly active catalysts for ethylene polymerization by the reduction of TiCl4 with organomagnesium compounds