Which element do kids get bored of studying?

Bohrium


The History of Polymers

Have you ever thought how did we come to depend on plastic, Teflon, Nylon and Lycra? Today the market is flooded with different materials. Modern life would be incomparably different without synthetic chemicals which are called as polymers.

Man-made fibres are used in clothing, carpets and curtains while plastics are used in innumerable domestic and industrial applications and artificial joints, and paints and cleaning materials, are all different forms of this important discovery. What is often forgotten is that at the beginning of the 20th century the chemistry of large molecules was unknown and their synthesis was definitely unthinkable.

Large Molecules

When a German scientist named Hermann Staudinger proposed in the 1920s that it was possible to have large molecules which were made up of many thousands of atoms, he was ridiculed by many other scientists. The common wisdom was that the structures of such materials as rubber and Bakelite were actually many small molecules which were held together by an unknown force.

Organic Synthesis

Hermann Staudinger stuck to his guns and, with his colleagues, he synthesised a series of organic molecules which were called poly (methanals). These compounds were long chains of repeating units, the units being -CH2O-. They are made by joining lots of methanal molecules together. The German scientists made chains of different lengths and showed that their properties changed depending on the length of the chains that were prepared.

Following this, the chemists working for Imperial Chemical Industries (ICI), soon discovered a polymer that reacted to organic molecules, ethylene which is now known as ethene and benzaldehyde, at very high temperature and pressure. The reaction failed to impress, but there was a small amount of a white, waxy substance on the wall of the reaction vessel. This was poly(ethene) or polythene, and soon ICI realised that they had a potentially useful compound.

The new material had many properties which made it unique. It was easy to form into different items and was tough and hard wearing and was impermeable to water and insulating to electricity. It was discovered in the 1930s and was soon being used in the Second World War to insulate the many metres of cables that were needed for the vital radar equipment that was used by the British.

HDPE

The development of the petrochemical industry after the war supplied the raw materials for this product. Then a catalysed method of producing high-density poly(ethene) (HDPE) was discovered by Karl Zeigler in Mulheim, Germany in the year 1950. Both these developments meant that the world would never be the same again as more and more uses for this plastic were discovered.

Soon other types of polymers were being developed. Some of the most important were poly (propene) by Giulio Natta in Milan, Nylon by Wallace Carothers in the US, poly (urethane) s that was used in Lycra, and polyesters soon became a very important raw material for the clothing industry.

The history of the development of polymers is nowhere near its end. New developments and advances are constantly being made and every year there are new patents for novel molecules which promise much. Only time will reveal how we will depend more on these compounds.

Tags :     polythene     nylon     plastic    


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