Types of Polymers

The word polymer comes from two Greek words that mean many units. The word describes a large molecule made from repeating copies of a smaller molecule that are hooked together by chemical bonds like beads on a string. There are many examples of polymers in nature and also in industry.

Synthetic Polymers

Humans make synthetic polymers in a laboratory or factory. Some of the most familiar examples are the strong and lightweight pp woven bags you use to carry food home from the grocery store. They are made from polypropylene, which is an extremely long molecule made of repeating propylene monomers. Another common polymer is polyester, a popular clothing fabric constructed from many esters. A third, familiar polymer is slime. When children mix borax with glue, they create long polymers made of repeating polyvinylacetate molecules. 

Natural Polymers

Nature also creates polymers for the benefit of living things. For example, shellac is similar in appearance to plastic but is a natural substance secreted by an insect in India and Thailand. Its long molecules are composed of alcohol and acid esters that repeat multiple times. The female insect uses the shellac to protect her offspring as they develop on the trunk of a tree. Silk also is an insect-produced polymer that humans harvest to make clothing. The repeating units of silk polymers are proteins that the insect larva uses to build a cocoon.

Biological Polymers

Biological polymers are also known as macromolecules, and are the basis of our bodies and the food we eat. The four main types and their monomers are listed below:

• Carbohydrates: Monosaccharides 
• Proteins: Amino acids
• Lipids: Fatty acids and glycerol
• Nucleic acids: Nucleotides

Carbohydrates are found in bread, pasta, and grains, and serve as the primary energy source for most organisms. Proteins are in animal muscles, milk, and eggs, but also come from plant sources such as beans and legumes. They are used for structure and also for energy. Saturated fats like butter and unsaturated oils from avocados and olives are examples of lipids. The body uses them for insulation and long-term energy storage. Nucleic acids are the genetic blueprints and are found in every living thing. The only cells in your body without nucleic acids are red blood cells because they do not contain a nucleus or mitochondria.

Chances are, there are many polymers all around you right now. How many different types can you name?