The history of polyolefins actually began in the 1890s with the synthesis of polymethylene from diazomethane. In the 1930s researchers in England discovered that ethylene at high pressure and in the presence of oxygen polymerized to a high molecular weight resin. Further research there and in the United States at still higher pressures yielded essentially straight chain, higher density polyethylenes. Early in the 1950s, groups in the United States and Europe independently discovered that linear, high-density polyethylenes could be made at low pressure over heterogeneous catalysts. Concurrently, groups catalytically produced polyolefin plastics from propylene and higher a-olefins. The inventorship of crystalline polypropylene was awarded to Phillips Petroleum Co. by United States courts in early 1980 (subject to final appeal). Commercial production of low-density polyethylene began in England (ICI) in 1939. High-pressure plants appeared in the United States (Du Pont and Union Carbide) and in Germa...

Stereoregular polymers and stereospecific polymerizations: The contributions of Giulio Natta and his school to polymer chemistry volumes I and II edited by G. Natta and F. Danusso. Pergamon: Oxford, 1967. Vol. I: 466 pp. Vol. II: pp. 467–888. Both vols. 6 in. × 912in. £15 15s per set of two volumes

History of Polyolefins

Crystalline organic high polymers in their solid state have very complex morphologies. This is due to the chainlike nature of their constituent molecules, which leads to crystallization behavior and morphologies that are in most aspects only rarely encountered in more traditional “small molecule” solids, and in other aspects are unique to polymers. Moreover, this chainlike nature leads to a wealth of phenomena and a rich diversity of morphological behavior that is, on the one hand, a boon to the experimentalist, for it provides an almost endless source of study, and, on the other hand, a source of despair for those who, like ourselves, attempt to summarize the behavior of these materials. There is a real danger that too great a preoccupation with the details of the morphology of one or two individual polymers will both obscure important aspects of behavior common to all polymers and also mislead the reader into perceiving a simplicity that in fact does not exist.

The Morphology of Crystalline Synthetic Polymers

New polyolefin resins, in spite of their simple chemistry, just carbon and hydrogen atoms, have become by design complex polymers with improved performance for the desired application. Besides the fundamental molar mass distribution, there are many other features that can be controlled when dealing with copolymers and new multireactor/multicatalyst resins. The average properties measured by spectroscopic techniques are not enough to define the microstructure of the new resins; it is necessary to fractionate the polymer according to certain parameters such as molar mass, branching, or stereoregularity. Separation techniques have become essential for the control and characterization of these polymers; nevertheless, full characterization is not a simple task and has demanded the development of new separation methodologies in recent years, and in many cases multiple separation techniques are required to define the microstructure. A review of the most important separation techniques with emphasis on the new technologies is given and the applications of these new polyolefin resins discussed.

Polyolefin Characterization: Recent Advances in Separation Techniques

Efficient catalysts for hydrocarbon polymerization have been prepared photochemically by reaction of mixed TiCl4 and Al2(CH3)6 adsorbate layers, in the scanned focus of a 257.2‐nm laser beam. Monolayer coverages of the photodeposited catalyst have been shown effective for in situ patterned polymerization of ethylene and acetylene at room temperature from the vapor phase organic monomers. Three‐micrometer spatial resolution has been obtained in selected‐area polymer growth. The chemical kinetics of the mixed‐adsorbate reactions and the effects of compositional changes on the catalytic activity of the laser‐photodepostied films have been studied.

UV laser photodeposition of patterned catalyst films from adsorbate mixtures

Polymer Blends: Introduction

Substance composed of macromolecules with repeating structural units

Citations

History of Polyolefins

The Morphology of Crystalline Synthetic Polymers

Polyolefin Characterization: Recent Advances in Separation Techniques

UV laser photodeposition of patterned catalyst films from adsorbate mixtures

Polymer Blends: Introduction