Key difference - monomer vs. polymer
Both monomer and polymer are widely used in industrial chemistry to refer to different types of materials and their constituents. The word "poly" literally means "many". And the word "mono" means "one" or "individually". Therefore, a polymer is a compound made up of many individual units, while a monomer is viewed as the single unit that is the repeating building block in a polymer chain . This is also the main difference between monomer and polymer.
What is a monomer?
As mentioned above, monomers are individual units that function as the building blocks of polymers. They are covalently to polymers bound . These are low molecular weight molecules that gradually add up to form a complex unit. When two monomers are put together they are called “dimers” and then continue to form trimers, tetramers, pentamers, etc. When a few dozen units add up, the system is called an “ oligomer ”.
A monomer can consist of a single type of molecule, but it can also consist of several types of molecules that are covalently bound. By definition, a monomer is a unit that is repeated within a polymer. Therefore, special care must be taken when breaking down a polymer into its monomer units. Proteins, which are polymers, are made up of repeating amide units and are therefore referred to as polyamides. As used herein, "amide" refers to the type of bond that binds the monomer units. When the monomers repeat, the bonds repeat too, hence the name. Likewise, nucleotides are the monomer units of DNA and RNA and cellulose consists of repeating D-glucose units. With respect to the synthetic polymers, rubber is made from repeating "isoprene" units, ethylene is repeated to form polyethylene , and propylene is repeated to form polypropylene . The chemical and physical properties of monomers differ from their macroscopic counterparts.
What is a polymer?
As mentioned above, polymers are very high molecular weight macromolecules made up of a large number of repeating units called monomers. Polymers can be built up from a single type of unit or from multiple types of units. However, since the monomer is defined as a repeating unit, it can be made of a single type or multiple types. When a single type of monomer is repeated, the polymer produced is referred to as a " homopolymer ". The process of forming the polymer from monomer units is known as “ polymerization ”. During the polymerization process, monomer units can be linked in different patterns. Two common categories include step growth polymerization and chain growth polymerization. In the step growth polymerization, each monomer unit adds up individually. And in the second method, chain growth polymerization , a few monomer units combine to form short chains before they attach to the growing polymer.
Polymers are synthesized chemically and also occur in nature. Some of the most common natural polymers are; Proteins (polyamides), DNA (polynucleotide), RNA (polynucleotide), cellulose (polysaccharide) etc. Examples of synthetic polymers are synthetic rubber, nylon, PVC, polyethylene, polypropylene etc. The polymer acts as a continuous macroscopic material while its chemical properties can be defined on the nanoscale, how the polymer chains interact through physical forces. However, the bulk properties of the polymers can be checked externally.
Difference between monomer and polymer
A polymer is a macroscopic material that consists of a large number of repeating individual units that are connected to one another.
A monomer is a single repeating unit that is covalently bonded to form polymers.
Polymers are complex molecules with a very high molecular weight.
Monomers are simple, low molecular weight molecules.
A polymer always has a single repeating unit.
A monomer can have different combination units.
Physical / chemical properties
Polymers are macroscopic molecules that are stronger than monomers and less sensitive to chemicals.
Monomers are small molecules on a microscopic scale that cannot be compared with the macroscopic properties of polymers. And they are more chemically reactive than polymers.
"Example vinyl monomer" by Chem538grp1w09 - own work. (Public Domain) via Wikimedia Commons
"RAFT Architecture" by Chem538w10grp4 - Own work. (Public Domain) via Commons