What Are Monomers And Polymers?

Monomers And Polymers: The basic building block of a polymer is a monomer. Through the process of polymerization, it is a single molecule that can interact with other monomers to create a polymer.

A monomer is a single molecule that can interact with other monomer molecules to build a polymer, as the name implies. It can be viewed as the essential building block of a polymer compound because it is the basic unit of a polymer. That makes defining a polymer fairly easy. It is a big molecule made up of tiny pieces, or monomers. Another name for a polymer is a macromolecule. A collection of two or more atoms linked together by chemical bonds constitutes a molecule.

Carbohydrates, lipids, and proteins are examples of frequently occurring polymers that are all composed of repeated monomer units. Units of fructose and glucose are combined to form the monomers of carbohydrates known as monosaccharides. Fatty acids and glycerol are also the building blocks of lipids. Nucleotides, which are monomers, are the source of the DNA or RNA in our bodies. Finally, amino acids are the monomer units that make up proteins, the body’s building components.

It is acceptable to state that a molecule must be able to interact with other monomeric molecules in order to be a monomer.

What Is a Monomer?

Low molecular weight hydrocarbon molecules make up monomers. Any chemical fully made up of hydrogen and carbon molecules is referred to as a hydrocarbon in chemistry. A monomer can also combine to make dimers, which are composed of two monomer units, trimers, and so forth.

Chemical bonds are used to join the monomer units of a polymer, maintaining the polymer’s ultimate configuration. Depending on how the monomer units are bonded together, a polymer can have several structures.

The fact that multiple monomer units have the same amount of carbon atoms but distinct configurations is interesting to note. Isomers are those compounds that have the same number of carbon atoms but different configurations. Isomeric monomers include substances like glucose, galactose, and fructose. Although they have comparable chemical formulas—that is, the same number of atoms in the molecule—their molecular arrangements are different, leading to the formation of three distinct compounds.

The polymeric substance is endowed with various features by various isomeric molecules of the same monomer unit.

What Is a Polymer?

A polymer is made up of monomer units that repeat and can be either natural or artificial. In our system, polymers play a significant role, as was previously mentioned. Additionally, polymers can be found in quartz, concrete, glass, paper, plastics, rubber, and other man-made materials.

Both homopolymers and heteropolymers are types of polymers. A homopolymer, like polyvinyl chloride, is made up of repeated units of the same monomer. Two or more distinct monomer units make up a heteropolymer. Due to the variety of amino acids bound together, proteins constitute a prevalent heteropolymer.

Covalent bonds, which include the sharing of electrons between the two atoms, hold repeating molecule units together. Comparatively speaking to other kinds of chemical bonds, this makes the bond rather strong. A polymer is stronger and far more difficult to break as a result. It’s exceedingly challenging to crack a crab’s strong shell since it’s made of the polymer chitin, which is what gives it its hard exterior.

Living things contain organic polymers that are essential to their survival, such as the cellulose and lignin found in plants. Lignin aids in the formation of plant cell walls, whereas cellulose is needed to give the same cell walls rigidity.

So, how do monomers combine to create these lengthy polymers? It occurs through a complex process called polymerization.

What Is Polymerization?

Polymerization is the process of creating polymers through a chemical reaction. Some chemical groups are lost throughout this process, which results in a different final product than what was anticipated. As a result, not all of the chemical characteristics of the original single monomer units are always retained by the polymer. Chain reactions and step reactions are the two forms of polymerization reactions.

As was already established, isomeric monomers tend to influence the manner that covalent bonding takes place, which changes the properties of a polymer, if they are present in the process.

A monomer typically has at least one carbon-to-carbon double bond, it should be emphasised. With its six electrons, a carbon atom can create single, double, or triple bonds with other atoms. The majority of them entail sharing one, two, or three electrons with other atoms, respectively, and have covalent connections. Atoms associate with one another to increase their stability, hence those atoms with an extra electron tend to be more reactive than others.

A free radical is any chemical compound that has a free electron that can attach to other atoms to generate other compounds. Similar to catalysts, these free radicals bind to the double bonds of a monomer unit to create the polymer. The free electron is transferred from the free radical to the outer carbon of the monomer unit as a result of the free radical’s breaking of the double bond and binding with the monomer. The hunt for other monomer units is then started by this free electron, and a continual process whereby monomer units bind to one another starts. This kind of polymerization is a chain reaction. These processes result in the production of high molecular weight polymers.

On the other hand, the step-reaction polymerization generates low molecular weight molecules and necessitates a higher temperature. Because byproducts like water or hydrochloric acid may be produced during the process, this is also known as a condensation reaction. These condensation polymerization processes frequently involve a monomer with dual functions. Bi-functional monomers are monomers having two distinct functional groups.

Polymerization by condensation diamine acid
step-reaction polymerization with a water molecule released. (Image courtesy of Calvero via Wikimedia Commons)

An atom or group of atoms known as a substituent creates a new molecule by swapping out one or more hydrogen atoms from the original hydrocarbon.

As a result, we can define a functional group as a particular substituent within a molecule that aids in giving the molecule a different chemical property. We can then create the polymer by using this bi-functional monomer to join with additional monomers in both directions.