Alexandre_parkes.jpg

Figure 1: A plaque commemorating Alexander Parkes invention of plastic in Birmingham, England

The dictionary defines plastic as a material that can be molded. Chemically plastics are polymers or substances composed of long chains of repeating molecules. The words plastics and polymers are often used interchangeably. Until the later half of the 19th century, all of the known polymers were naturally existing ones. Some examples are tortoise shells, bitumen and natural rubber (Mossman 1997). The first true man-made polymer was synthesized by Alexander Parkes in Birmingham, England in 1862. This was not a truly synthetic polymer. The polymer was modified from naturally existing polymers so this was a semi-synthetic polymer. Parkes called his polymer Parkesine and used it to create an assortment of products such as combs, chess pieces, and dentures.[1]

The next breakthrough in polymer chemistry came in 1870 when John Hyatt, an American inventor, discovered that camphor reacts with cellulose nitrate and produces a new product. Hyatt called his product Celluloid. Celluloid is a flammable substance and its flammability was used as an advantage during World War II where British planes threw celluloid fire-leaves over German cities. A replacement for celluloid was cellulose acetate, which had a low combustibility.[1] Cellulose Acetate was first prepared by Paul Schutzenberger, a French chemist, in 1865. Schutzenberger heated cotton with acetic anhydride at 130-140oC. Cellulose acetate was commercially produced during World War I (though the procedure had been significantly refined by then) to coat the fabric wings of planes. After the war more cellulose acetate was being produced than needed and companies were looking for a market for cellulose acetate. Luckily, scientists quickly found ways to utilize the cellulose acetate in a marketable form and started producing rods, sheets, lamp shades and toys.[1]

All the previously mentioned polymers are semi-synthetic polymers. The first truly synthetic polymer was invented by Leo Baekland, a Belgian immigrant in USA. Baekland reacted phenol and formaldehyde under controlled conditions to produce amber coloured resins. Baekelan called his material phenolic resin. The market for phenolic resins was huge because of its properties , such as resistance to ignition and firmness. These properties made the phenolic resin ideal for use in plugs, insulators, radio cases and electric hot-water bottles.[1]

The next big breakthrough in synthetic polymers came in 1933 when polyethylene was accidentally discovered at ICI, Winnington in UK. Scientists at the ICI factory were conducting high-pressure reactions of alkenes with aromatic compounds. In an experiment that involved the reaction of benzaldehyde with polyethylene, a mistake led to the mixing of ethylene gas and oxygen in a high pressured reaction chamber.[1] The oxygen served as a catalyst, converting some of the ethylene to polyethylene. The discovery of polyethylene came at a time when tension in Europe was high due to Adolf Hitler rearming Germany. On September 1, 1939, the day Hitler's army invaded Poland, construction of the first 100-ton-per-year polyethylene plant was started in England.[1] For the duration of the war, all the polyethylene produced by ICI was for war purposes and no scientific paper on polyethylene was published until after the war. As soon as the war ended, there was an abundant amount of polyethylene. Soon ICI was looking for ways to market polyethylene for commercial products. A market for polyethylene finally emerged in 1953. First came polyethylene washing-up bowls, then dolls and bottles, and finally the ubiquitous plastic bag.[1]

Today, polymers have become a mainstay of industrial complexes. They are used in high-technology items like smartphones & computers and in basic everyday items like water bottles. The problem with the polymers currently in use is that they don't easily degrade. These polymers persist in environment for years and are a huge problem, because of the space they take and the damage they cause to plant and animal life over time. These problems have caused a huge segment of market to demand biodegradable polymers. Of course, there is already a large market of biodegradable polymer products made from naturally existing biopolymers. Textile products such as, cotton, wool and silk are a good examples of these bio polymers. Today we need new biodegradable polymers, synthetic or semi-synthetic, that degrade in a reasonable amount of time and can replace polymers that are not biodegradable or not easily biodegradable.


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  1. ^ Mossman S, editor. 1997.Early plastics: perspectives 1850-1950. London: Leicester University Press.