http://www.ck12.org Chapter 3. Chemical Interactions
3.30 Carbon Monomers and Polymers
- Define polymer and monomer.
- Identify natural and synthetic carbon polymers.
You probably recognize this image as the great seal of the United States. The motto on the seal,E pluribus unum, is
Latin for “out of many, one.” It refers to the formation of one country out of many states. Large carbon compounds
could have the same motto. Can you guess why? In this lesson, you’ll find out.
Out of Many, One
Carbon has a unique ability to form covalent bonds with many other atoms. It can bond with other carbon atoms
as well as with atoms of other elements. Because of this ability, carbon often forms polymers. Apolymeris a
large molecule that is made out of many smaller molecules that are joined together by covalent bonds. The smaller,
repeating molecules are calledmonomers. (The prefixmono- means “one” and the prefixpoly- means “many.”)
Polymers may consist of just one type of monomer or of more than one type. Polymers are similar to the strings of
beads pictured in theFigure3.48. Like beads on a string, monomers in a polymer may be all the same or different
from one another.
Natural Carbon Polymers
Many polymers of carbon occur naturally. Two examples are rubber and cellulose.
- Rubber is a natural polymer of the monomer named isoprene (C 5 H 8 ). This polymer comes from rubber trees,
which grow in tropical areas. Structural formulas for rubber and isoprene are shown in theFigure3.49. Note
that just a small section of the rubber polymer is represented by the structural formula.