What is a Monomer? Definition, Examples, and Applications

A monomer is a small molecule that can react with other molecules of the same type to form a larger molecule called a polymer. Monomers are the building blocks of plastics and other synthetic materials. They are typically made up of a single molecule, hence the name "monomer," which means "one part."

Monomers can be either natural or synthetic and can be derived from a variety of sources, such as petroleum, plants, or animals. Some common examples of monomers include:

1. Ethylene (CH2=CH2), which is used to make polyethylene plastic.
2. Propylene (CH2=CH-CH2), which is used to make polypropylene plastic.
3. Styrene (C8H8), which is used to make polystyrene plastic.
4. Vinyl chloride (CHCl=CH2), which is used to make PVC (polyvinyl chloride) plastic.
5. Lactic acid (C3H6O3), which is used to make biodegradable plastics.
6. Caprolactam (C6H11NO2), which is used to make nylon 6 plastic.
7. Adipic acid (C6H10O4), which is used to make nylon 6,6 plastic.
8. Isoprene (C5H8), which is used to make synthetic rubber.

Monomers can be joined together in a variety of ways to form different types of polymers, depending on the specific monomer and the conditions under which the polymerization reaction takes place. Some common methods of polymerization include:

1. Chain-growth polymerization, in which monomers are added one at a time to a growing polymer chain.
2. Radical polymerization, in which monomers are converted into radicals that react with other monomers to form a polymer.
3. Condensation polymerization, in which two monomers react together to form a larger molecule and release water as a byproduct.
4. Addition polymerization, in which monomers are joined together through a chain reaction mechanism.

Overall, monomers play a critical role in the production of many synthetic materials that are used in a wide range of applications, from plastics and adhesives to fibers and coatings.