When Wallace Carothers invented nylon, he made a polymer with a structure similar to that of silk. Natural materials inspired his work, and now we're going to take a look at some of those natural polymers.

Rubber

Natural rubber is one of the more unusual materials found in nature. It can be stretched and it snaps back to its original shape. It's also waterproof. What more could anyone want? A lot of different plants produce rubber, but the most important is the hevea tree (hevea brasiliensis). Natural rubber's scientific name is polyisoprene, and it has a repeat unit like you see on your right.

Starch and Cellulose

Starch and cellulose are both made from the same monomer, glucose. Glucose is a simple kind of sugar that your body uses for fuel. Starch is found in foods like bread, potatoes, corn, and rice. Your body breaks it down to get the glucose it needs.

On the other hand, cellulose is a polymer we can't digest. It is the main component of cotton and wood (and therefore paper), and it makes very strong fibers. Also, even though we can't digest cellulose, certain animals can. Termites can digest the cellulose in wood, while cattle and sheep happily get their nourishment from the cellulose in grass.

Proteins

Proteins are the family of polymers that inspired nylon. Wallace Carothers suspected that silk, one kind of protein, was a polyamide. So he decided to make a synthetic polyamide when he set out to make a synthetic fiber. But silk is just one kind of protein. Your skin, hair, and fingernails are made of a protein called keratin. In your blood, a protein called hemoglobin carries oxygen to your cells, while other proteins called antibodies fight disease. One amazing family of proteins are the enzymes. Enzymes are catalysts; that is, they speed up chemical reactions in your body. Some of them can make chemical reactions take place a million times faster than they would without an enzyme.

The body polymerizes amino acids to make proteins.