British chemists Reginald Gibson and Eric William Fawcett stumbled on polyethylene in 1933, by a stroke of luck. They went public with the discovery, but German scientists doubted their conclusions — a tactical mistake Britain would later exploit in World War II.
Gibson and Fawcett inadvertently discovered PE resin at Imperial Chemical Industries plc's laboratory in Winnington, England, when they subjected ethylene to high pressure and temperature. On March 24, 1933, they heated the ingredients and increased the pressure to about 28,000 pounds per square inch. When they dismantled the equipment after leaving it on all weekend, they found a waxy solid. Analysis of the 0.4 gram of material indicated they had a polymer.
Gibson and Fawcett's process, however, was unreliable. Sometimes it yielded a small amount of polymer; at other times, the ingredients turned into carbon residue. A few years of experiments indicated traces of oxygen were needed to catalyze the reaction. Afterward, predictable quantities of PE could be made at will.
After 1933, ICI's research on PE slowed because company management did not see it as commercially useful. The PE discovery was in the domain of ICI's dyestuffs division, which had no interest in the mysterious, waxy substance. Fawcett was reassigned and others continued his work with PE. He did, however, gain ICI's permission to share the results at a Faraday Society scientific meeting in Cambridge, England, in September 1935.
When Fawcett reported the PE discovery, preeminent German chemists, including Nobel Prize winner Hermann Staudinger, were present, but they didn't believe Fawcett's conclusions, according to ICI: The Company That Changed Our Lives. Staudinger, a major authority on polymers at the time, could have made his biggest mistake. By ignoring Fawcett's results, German researchers did not pursue PE production. But Britain found it an ideal insulator for radar equipment, giving it a competitive edge during World War II.
In the war's early stages, the material was used in new short-wave radar and allowed Britain to make smaller radar sets for airplanes and ships as well as for coastal defense installations. The country commissioned British PE production in 1940. About 220,000 pounds were made in Wallerscote, England, for war effort.
When the German military debated whether to escalate the war in the Atlantic theater, German Admiral Karl DÃ¶nitz suggested they delay such action. DÃ¶nitz told Adolf Hitler in May 1943: “What is now decisive is that enemy aircraft have been equipped with a new location apparatus ... which enables them to detect submarines and to attack them unexpectedly in low cloud, bad visibility or at night.”
During the war, ICI shared its technology with DuPont Co., which began building a PE plant in the United States. Union Carbide Corp. also constructed a U.S. PE plant, so that during the whole of World War II — from 1939-45 — total Allied production was about 8 million pounds, said Eddie Hill, a retired senior instrument engineer with ICI's PE plant in Wilton, England. Hill maintained documentation for ICI's PE plants until those archives closed.
ICI researchers applied for British patents from 1936-37 and registered the trade name Alketh for PE. But the generic term polythene became more widely used in Britain, and in North America polyethylene was the preferred name.
Early uses of PE centered on cable insulation. Eventually the resin was chosen as the insulation for the first around-the-world telephone cable.
PE relied on catalyst innovations to become the ubiquitous resin it is today. Early work relied on very high pressures to turn ethylene into PE. Catalyst advances led to milder polymerization conditions, a proliferation of grades and even more uses.
In the late 1950s and early 1960s, Ziegler-type catalysts from Germany made it possible to fabricate linear-chained PE with higher densities than the first generation. German chemists Karl Ziegler and Erhard Holzkamp contributed important work, and in 1953 Holzkamp invented high density PE. Two years later, the first HDPE pipe was extruded.
As new HDPE grades hit the market, so did a flood of products including bottles, buckets and housewares.
In the U.S., Phillips Petroleum Co. and Standard Oil Co. were developing their own HDPE technologies at a time when PE production was supported by a large oil and gas industry that provided cheap materials to make ethylene. Britain, by contrast, in the early years relied on fermenting sugar from molasses to ethyl alcohol and reacting the ethanol to ethylene before polymerizing it into PE. In Phillips' early PE production, the firm made a lot of off-spec resin, but a use was found — a circular HDPE tube called the Hula Hoop, which became a U.S. fad after it debuted in 1957.
Catalyst development continued, with the aim of making more precise resins more economically. Metallocene catalysts, developed by Walter Kaminsky and HansjÃ¶rg Sinn in 1976, made PE polymer chains easier to control. Modern catalysts make it possible to create copolymers, further stretching the properties envelope for the PE family.
From the 0.4 gram isolated by Gibbons and Fawcett in 1933, PE has grown into a global industry producing more than 90 billion pounds a year, the largest-volume thermoplastic in the world.