#50 Science in History
27th March 1933
Today in 1933, two British scientists discover polyethylene (polythene).
Polyethylene was discovered by Reginald Gibson and Eric Fawcett, who were working for the Imperial Chemical Industries (ICI) research laboratory in Manchester, England. They were investigating the properties of ethylene gas, a by-product of oil refining, when they discovered that under certain conditions, ethylene could polymerise (join together), to form a white, waxy substance.
Initially, the ICI scientists had trouble producing a high-quality polymer that could be used for commercial applications. However, in 1935, they were able to develop a new production process, which involved pressurizing and heating ethylene gas in the presence of a catalyst. This new process produced a much higher quality polyethylene that was strong, flexible, and had a low density.
The discovery of polyethylene came at a critical time in world history. In the years leading up to World War II, there was a growing demand for synthetic materials that could be used to replace natural materials that were in short supply due to the war. Polyethylene quickly became an important material for the war effort, as it was used to make a wide range of products, including gas masks, insulation for radar equipment, and parachute cords.
Both the UK and USA controlled the production of polyethylene during World War Two. Strategic resource management with industrial production in support of a larger national effort ensured that the war effort was supported by a robust and efficient industrial base.
The government established a system of production quotas and allocated raw materials, such as ethylene gas and catalysts, to companies based on their production capacity and their contribution to the war effort.
In the United States polyethylene was designated as a critical material for the war effort. The government provided funding for the construction of new polyethylene production facilities and encouraged companies to develop new uses for the material. As a result, the production of polyethylene in the United States grew rapidly, from just a few thousand pounds per year in the late 1930s to over a million pounds per year by the end of the war.
After the war, the demand for polyethylene continued to grow, as it was used in a wide range of new applications, including plastic bags, milk jugs, and PVC pipes. In the 1950s and 1960s, new processes were developed for producing high-density and low-density polyethylene, which had different properties and were used for different applications.
Today, polyethylene is one of the most widely used plastics in the world, with annual production exceeding 100 million metric tons. It is used in a wide range of applications, from food packaging to medical implants, and is known for its low cost, high strength, and excellent chemical resistance. Most notably, polyethylene is used to make many types of bags, including grocery bags, trash bags, and sandwich bags. In fact, it is estimated that over one trillion plastic bags are used worldwide each year, many of which are made from polyethylene.
One of the interesting properties of polyethylene is its ability to float in water, which has led to its use in a variety of water-related applications. For example, polyethylene is used to make buoyancy aids for swimmers, fishing nets, and even small boats.
In addition to its many practical applications, polyethylene has also been used in art and design - the British artist Tom Price has used polyethylene to create sculptures that explore the properties and potential of this versatile material.
Despite its many benefits, polyethylene also has some drawbacks. One of the biggest concerns is its impact on the environment, as it is not biodegradable and can persist in the environment for hundreds of years. In recent years, there has been growing interest in developing more sustainable alternatives to polyethylene, such as biodegradable plastics made from plant-based materials.
Some interesting facts and trivia about polyethylene:
Polyethylene is the most commonly recycled plastic in the world.
It’s a thermoplastic, which means it can be melted and re-moulded many times without degrading its properties.
Polyethylene is resistant to most chemicals, including acids, bases, and solvents.
It can be made in a wide range of colours, including translucent and opaque versions.
It is also used in a wide range of medical applications, including joint replacements, sutures, and catheters.
The largest producer of polyethylene in the world is ExxonMobil, which produces over 20 million metric tons of the material each year.
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