It is hard to imagine a modern life without polymers. They are literally everywhere. What makes them so useful and unique? Chemists look inside the structure of a matter in order to explain specific chemical or physical properties. Polymers do have unusual structures. Their large molecules consist of particular segments that are repeated by some pattern. The segments are called monomers. As a result of polymerization, monomers completely change their properties. For example, polyethylene (-CH2-CH2-)n, “the largest tonnage plastic material”, is a waxy solid polymer (Nicholson 6). However, ethylene by itself is a gaseous matter.
Even though man-made polymers were introduced relatively recently, naturally occurring polymers, like bones, leather, cotton, cellulose, horns, silk, shells, amber, sap of trees, and bee wax, were familiar to a human being a long time ago. Ancient Greeks and Egyptians mixed pitch, beeswax, and gum arabic with minerals to prepare a blend for covering walls and make them less prone to destruction. Ancient Chinese extracted sap from trees and used it to glaze wood. There is a written evidence from the Middle Age that was left by Theophilus, a monk, that has information regarding a preparation of a varnish from linseed oil and pine tree gum (Eliott 55). Aborigines of South America played a game with elastic balls that were made from resin latex (-CH2-C(CH3)=CH-CH2-)n collected from Hevea trees. The description rubber ball was first documented in 1496 (Gerdeen and Rorrer 2). Besides, Morawetz reported that they used the natural rubber to make bottles, shoes, and special fabrics (32). As it is seen, at first, people used available polymers as they are found in nature and have not made significant alterations to enhance their quality.
After rubber was introduced to Europe by Cristopher Columbus, the interest to this elastic material increased in the rest of the world. In 1823 Charles Macintosh used natural resin and benzene to make a special insulating coat for waterproof clothes (Freinkel 93). Gutta percha, another natural resin extracted from trees found in Southeast Asia, was used to coat first submarine cable (Eliott 60). Natural resin was useful for its elasticity and insulation properties, but it was prone to deformation due to temperature changes. Charles Goodyear attempted to improve its quality by heating resin with sulfur. As a result, he got the first semi synthetic polymer which was more durable with enhanced properties. The modern vulcanization process is based on Goodyear invention (Patterson 6).
Another factor that pushed humanity to manufacture first synthesized polymers, were running low of available natural sources of polymers. Elephants and hawksbill turtles were close to being extinct. They were “unhappy suppliers” of materials from which widely used items, such as combs, billiard balls, and piano keys were made (Freinkel 85). Businessmen made a fortune from making billiard balls out of ivory. Apparently, Gerden and Rorrer informs that they were so afraid to lose their business that they offered ten thousand dollars in gold to anybody who finds a decent replacement for the material and save them from going bankrupt (75). In the attempt to get the prize, John Wesley Hyatt, a yang ambitious fellow, invented a so-called “celluloid” or cellulose nitrate by treating cotton with nitric acid and adding camphor oil to make it moldable. Although, celluloid could not replaced ivory for making billiard balls due to its volatility, lack of bounciness, it found its use to make combs and other household items. Besides, this invention was the first step to produce photographic films that were made from the amended version of celluloid, cellulose acetate. Celluloid became the first mass produced synthetic polymer.
Meanwhile, electricity became widely available and new cheap materials for electrical insulators were needed. People used to make insulators from natural polymer shellac, which is a type of resin extracted from female lac beetles secretion. However, there was a need in a more easily obtained material with the same electrical insulating properties.According to Patterson (9), in 1907 Bakeland came up with his new discovery, a phenol formaldehyde resin (-C6H3OH-CH2-)n, commercially named as “Bakelite”. Bakelite was a plastic heat resistant material moldable into any shape and did not conduct electricity. Dr. Bakeland also added wood dust in order to overcome its brittleness.
Witnessing commercial success of first truly synthesized plastic, inventors and scientists stoped searching for materials that was a simple copy of natural polymers. They started to synthesize new materials with even better properties. Polystyrene found its application in protective packaging, different types of containers, bottles, and tableware. It can be transparent or colored, rigid or puffed up with air. Nylon, a revolutionary material in fashion, was invented as a result of attempts to make an artificial silk. Progress in chemical industry went so far that polymers with unbelievable properties were synthesized. For instance, Teflon (-CF2-CF2)n is an inert, hydrophobic material which has a surface that nothing could stick. Kevlar is a fabric which is strong enough to be used for body armor (-CO-C6H4-CO-NH-C6H4-NH-)n. New materials surpassed Bakelite due to their ability to be remolded and reshaped. Thermoplastics, such as polystyrene, nylon, Teflon and others, could be reused simply by melting because they did not lose their initial properties unlike thermosets like Bakelite.
With an increase demand of new materials with advanced properties that was brought by industrialization, production of synthetic polymers boosted up. Unfortunately, progress did not bring only positive results. Huyhua states that there are more cases of discarding and combustion of used plastics rather than their recycling. This leads to environmental and health issues. The need to sorting wastes prevents manufacturers from recycling large amount of plastics. Therefore, new technology that allows to skip this labor-intensive step is needed. The perfect answer to this problem would be usage of biodegradable polymers. They can be made out of biomass products like polysaccharides and proteins, extracted from microorganisms, or synthesized from oil-products (Nair and Laurencin 693).
Naturally occurring polymers were familiar to people and used from ancient times. Increase in demand and desire to live better made humankind to search alternatives for them. Industrialization led to even more need of mass produced synthesized improved ‘super’ materials. Even though one could complain that we live in ‘a Plastic age’ now and have less natural items, plastics made our lives much easier and comfortable.
Eliott, Eric. Polymers and People: an Informal History. Philadelphia: Beckman Center for the History of Chemistry, 1990. Print.
Freinkel, Susan. Plastic: a Toxic Love Story. Boston: Houghton Mifflin Harcourt, 2011. Print
Gerdeen, James, and Rorrer, Ronald. Engineering Design with Polymers and Composites. New York: CRC Press, 2012. Print.
Huyhua, Samantha. “Recycling Plastics: New Recycling Technology and Biodegradable Polymer Development”. Illumin: a review of engineering every day 15.1 (2014). University of Southern Carolina: n. pag. Web. Mar. 2014
Moravetz, Herbert. Polymers: The Origins and Growth of Science. Toronto: John Wiley and Sons, 2002. Print.
Nicholson, John. The Chemistry of Polymers. 3rd ed. Cambridge: The Royal Society of Chemistry, 2006. Print.
Nair, Lakshmi and Laurencin, Cato. “Biodegradable polymers as biomaterials” Progress in Polymer Science. Aug-Sep. 2007: 762-798. Print.
Patterson, Gary. A Prehistory of Polymer Science. Pittsburg: Carnegie Melon University, 2012. Print.