A polymer is a large molecule made up of repeating subunits called monomers that are linked to one another by chemical bonds. Natural polymers are common in everyday life. Many are produced by living organisms. There are also synthetic polymers, which are made in a lab through chemical reactions, usually involving petrochemicals. Here is a list of natural polymers, their sources, and their monomers.
All four of the main classes of biological molecules (nucleic acids, proteins, carbohydrates, lipids) include polymers. Most of the natural polymers encountered in everyday life are proteins, such as keratin in wool and hair; cellulose from plants; and collagen in skin.
Even elements can form natural polymers. For example, graphene is a polymer made of carbon subunits. Under certain conditions, the element sulfur forms a natural plastic. Obsidian (natural glass), diamond, quartz, and other minerals are natural inorganic polymers.
Examples of Natural Polymers and Their Monomers
|Natural rubber (latex)||isoprene||rubber tree, dandelion, chicle|
|DNA and RNA||nucleotides||living organisms|
|Hair, wool, nails, hooves, claws||α-keratin||all vertebrates|
|Chitin||N-acetylglucosamine||arthropod exoskeletons, fish scales|
|Feathers, reptile scales and shells||β-keratin||birds and reptiles|
|Pectin||mostly D-galacturonic acid||plants|
|Silk||fibroin made mostly from alanine and glycine||insects, arachnids|
The earliest synthetic polymers were actually semi-synthetic because they were modifications of natural polymers. For example, nitrocellulose is a synthetic polymer made from cellulose. Today, many synthetic polymers found in daily life are made from petroleum.
Examples of synthetic polymers include:
- Bakelite, the first synthetic plastic
- Epoxy resin
- Silly putty
- Cowie, J.M.G.; Arrighi ,Valeria (2007). Polymers: Chemistry and Physics of Modern Materials (3rd ed.). Boca Raton, LA: CRC Press.
- Sperling, Leslie H. (2006). Introduction to Physical Polymer Science (4th ed.). Hoboken, NJ: John Wiley & Sons.
- Young, Robert J.; Lovell, Peter A. (2011). Introduction to Polymers (3rd ed.). Boca Raton, LA: CRC Press, Taylor & Francis Group.