The History of (Plastic) Polymers

Today we often think of plastic polymers as modern magical materials brought to us in chemists labs. In reality mankind has run into this interesting material naturally for thousands of years. The ancient Mesoamericans processed a natural rubbery material into balls and other objects as early as 1600 BC![1]  References about natural materials used as adhesives, coatings, and fillers are even referenced in the Old Testament of the Bible[2].

Polymers are substances having molecules with a high number of repeating molecules. Called monomers, they form a sequential chain[3].  There are naturally occurring and synthetic polymers. Naturally occurring polymers are starches, latex, cellulose, and proteins[4].

These very long molecules allow the construction of many interesting materials from fibers, films, adhesives, resistant paints, and tough but light solids that have transformed our modern world.

Ebonite or hard rubber, was first discovered in the early 1800s. This was the first thermosetting material used. Thermosetting is a resin pre-polymer that is in a soft or viscous state that changed into a polymer in the process of curing. This process (curing) is caused by an action of heat or radiation often under pressure. This is called Thermoset.

In 1839, Goodyear invented vulcanized rubber, and Eduard Simon discovered polystyrene. Simon was a German apothecary[5]. Of course, we know the Goodyear name because of the tires that we still buy for our cars.

Charles Goodyear walked in to the Roxbury India Rubber Company, the first American rubber manufacturer in 1834. He was trying to sell a new valve he had devised for rubber life preservers. The company was unable to do business as they were doing badly and not sure they could stay in business. Taking young Goodyear into the storeroom, they stared at rack after rack of rubber goods that had melted into a big mess of foul-smelling glue due to the hot and dry weather. Customers were returning thousands of melted rubber products. This became “rubber fever,” and soon demand shifted to a new waterproof gum from Brazil. Goodyear, returning to Philadelphia was thrown into debtors’ prison where he began to work on rubber experiments. Goodyear reasoned that this gooey substance might be mixed with a dry powder to take away the stickiness.

When out of jail again, he continued his experiments. He made up rubber overshoes, but that summer they also sagged into shapeless paste. Continuing his experiments he tried sulphur and by mistake his rubber was thrown on a hot stove. Instead of charring, it hardened into weatherproof rubber. He realized he could alter the formula and make many different products. It was the first and most versatile of the modern “plastics.[6]

In the 1850s at the Great Exhibition of London, Alexander Parkes of England discovered a solid residue that was left when photographic solvent evaporated. This residue was a hard, elastic, and waterproof substance. He described it as a horn-like substance. Think of a cow horn and its almost plastic-like quality. He later patented the process of waterproofing woven fabrics using his discovery[7].

The same process was also worked on by the Hyatt brothers, who after some legal battles, called a similar substance cellulose. Today it is called cellulose nitrate[8]. The word “plastic” was introduced in 1925[9]. In the same decade a German chemist with experience in studying natural compounds proposed that these substances were made up of macromolecules with 10,000 or more atoms[10]. He studied a polymeric structure for rubber which was based on repeating monomers. He eventually was awarded the Nobel Prize for his work.  This understanding helped fuel the rapid development that would follow.

Developmental work continued almost unbounded through the first half of the twentieth century.  Chemists eventually realized that many natural resins and fibers were polymers. The first synthetic plastic was the introduction of Bakelite, invented by Leo Baekeland in 1907. His company produced laminating varnish, molding material, and cast resin. The molding product sales exceeded laminating material in the 1930s[11].  Some of the first products were motor distributer rotors, radios, and the Ericsson Telephone. Many toys were made from Bakelite replacing cast iron and tin toys in the 1940s and 1950s. They were more durable, didn’t scratch, and could be made in colors that were in the material, and didn’t scratch off.

During the first half of the twentieth century, at least 15 new classes of polymers were synthesized. The commercial success since then has been substantial.

A range of materials including natural polymers, modified natural polymers, thermosetting plastics and thermoplastics, have been developed. More recently biodegradable plastics are being developed. They have a range of unique properties and a wide range of temperature usage. They are chemical and light-resistant. They are strong, tough, and low cost compared to other materials.

From these humble beginnings today over 310 million tons of plastic are used annually worldwide, and it will continue to grow about 5 percent per year. The different types of plastics expanded the industry into areas not imagined in the early days of polymers.

Polyethylene was developed by Reginald Gibson and Eric Fawcett in 1933. It was used as a low-density resin (LDPE) by 1935. In 1953, high-density polyethylene (HDPE) was invented[12]. About 25 processes are used today in manufacturing the full range of PE’s. This is the second most used resin type. It is used to make plastic film, milk jugs, sandwich bags, cling wrap, pipes and insulation for electric cables[13].

PVC (Polyvinyl chloride) was commercially viable in the 1920s. PVC differs in chemical structure because it contains chlorine as well as carbon and hydrogen.  This white powder needs a blend of other substances to give it a wide range of attributes. It is used in piping, medical devices, shutters doors, and upholstery and other industrial applications.

PS, Polystyrene, was produced in the 1930s by the well-known BASF German company. It is in two primary forms:  A general purpose and high-impact grade. We know about polystyrene cups, and a modified form is also an excellent insulating medium for homes and industrial buildings. It is also used in TVs and other electronic goods.

PET was discovered in 1941. Today we recognize this polyester film in many forms of bottles which are clear and resist Ultra Violet light. It is transparent, lightweight, and resists carbon dioxide permeation[14].

Polypropylene was discovered by Giulio Natta in 1954. Commercial production followed in 1957. This is the most widely used plastic and is manufactured around the world.  This is because it is a low-cost and versatile material. It can be thermoformed, blown film blow-molded, injection-molded and extruded into a wide range of products such as stackable crates for storage and shipping, small, thin-walled containers (yogurt, margarine tubs, food trays), glass replacement, window frames, water pipes and household goods, such as bowls, combs, toasters, hair dryers, and film wrapping for clothing and many other applications.

Perhaps the plastics world came of age in the movie The Graduate, where the term “the future is plastics,” was uttered to Dustin Hoffman in the ‘60s. This phrase has certainly come true. Since then the industry has grown 20 times.

Figure 1. Chart from Consultancy.UK, Website – http://www.consultancy.uk/news/3279/global-transition-needed-to-a-circular-economy-for-plastics.

 

Most plastics need additives to create various characteristics described above. They may be the most expensive component of a product, and the range makes formulating polymers a true “chemistry set.” Many materials, forms, and additives create a huge variety of products options.  Plastics Manufacturers are well aware of all these types of variations but still rely on the polymer companies to assist with the exact formulations.

Today we have many social benefits of plastics. They are lightweight, sterile, and relatively easy to manufacture.  The strength-to-weight ratio assists car manufacturers in pushing up gasoline mileage. Stronger, lighter packaging and bottles are convenient and save millions of dollars in transportation weight. We have many products that would cost much more in wood, metal, glass, or ceramics, saving billions of dollars for consumers.

Yet all this success and usefulness does come at a price. The simple durability of the material makes plastic a material that lasts and lasts and lasts. It breaks down very slowly in a natural environment and, therefore, becomes a risk when disposable products are not recycled. The future of plastic looks bright, but clearly the industry must work harder at creating both better recyclable plastics and new bio-based plastics that break down in the environment faster than they do now.  Plastic has become so successful, that it must now deal with the mass of plastic produced. We must have plastic, but we must also keep it from existing forever!

[1] US Natural Library of Medicine, National Institute of Health, Applications and Societal Benefits of Plastics, Anthony L. Andrady and Mike A . Neal, July 27, 2009. Web site https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2873019/

[2] The History of Plastics, SPI, The Plastics Industry Trade Association, https://www.plasticsindustry.org/AboutPlastics/content.cfm?ItemNumber=670

[3] Chemical of the Week, University of Wisconsin-Madison, Professor Bassam Z. Shakhashiri. http://scifun.chem.wisc.edu/chemweek/polymers/polymers.html

[4] Ibid

[5] US Natural Library of Medicine, National Institute of Health, Applications and Societal Benefits of Plastics, Anthony L. Andrady and Mike A . Neal, July 27, 2009. Web site https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2873019/

[6] Goodyear Corporate Web site, https://corporate.goodyear.com/en-US/about/history/charles-goodyear-story.html

[7] The History of Plastics, SPI, The Plastics Industry Trade Association, https://www.plasticsindustry.org/AboutPlastics/content.cfm?ItemNumber=670

[8] Ibid

[9] The History of Plastic. History of Plastic – Origin, Inventors and Facts, http://www.historyofplastic.com/

[10] Michigan State University, Department of Chemistry, Polymers, https://www2.chemistry.msu.edu/faculty/reusch/virttxtjml/polymers.htm

[11]  Bijker, Wiebe E. (1997). “The Fourth Kingdom: The Social Construction of Bakelite”. Of bicycles, bakelites, and bulbs : toward a theory of sociotechnical change (1st MIT Press pbk ed.). Cambridge, Mass.: MIT Press. pp. 101–198.ISBN 9780262522274. Retrieved 2 September 2015.

Photo credits: {{Information |Description=Ericssons Bakelittelefon 1931 |Source=egen bild |Date=2007 |Author=~~~~ |Permission=själv laddat upp |other_versions= }}  https://commons.wikimedia.org/wiki/File:Ericsson_bakelittelefon_1931.jpg

[12] History of Physical Chemistry of HDPE.2

Page https://plasticpipe.org/pdf/chapter-1_history_physical_chemistry_hdpe.pdf

[13] US Natural Library of Medicine, National Institute of Health, Applications and societal benefits of plastics, Anthony L. Andrady and Mike A . Neal, July 27, 2009. Website https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2873019/

[14] Ibid

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