The polymers They are large molecules (macromolecules) that are formed by the union of two or more smaller molecules which are called monomers. The monomers are linked to each other by covalent bonds.
The polymers are compounds very important, since some fulfill vital functions in living beings. For example: proteins, DNA. Many of them are present in nature and in practically everything that surrounds us. For example: plastic in a toy; the rubber in car tires; the wool in a sweater.
Depending on their origin, polymers can be classified into: natural (such as starch or cellulose) semi-synthetic (such as nitrocellulose) and artificial (such as nylon or polycarbonate). In addition, these same polymers can be classified according to the polymerization mechanism (the process that the monomers go through to form a chain and form a polymer), according to their chemical composition and according to their thermal behavior.
According to its origin:
- natural polymers. They are those polymers found in nature. For example: DNA, starch, silk, proteins.
- artificial polymers. They are those polymers created by man through the industrial manipulation of monomers. For example: plastic, fibers, rubber.
- semi-synthetic polymers. They are those polymers that are obtained by transforming natural polymers through chemical processes. For example: ethonite, nitrocellulose.
According to the polymerization process:
- Addition. It is a type of polymerization that occurs when the molecular mass of the polymer is an exact multiple of the mass of the monomer. For example: vinyl chloride.
- Condensation. It is a type of polymerization that occurs when the molecular mass of the polymer is not an exact multiple of the mass of the monomer. This happens because in the union of the monomers there is a loss of water or some molecule. For example: the silicone.
According to its composition:
- organic polymers. They are polymers that have carbon atoms in their main chain. For example: wool, cotton.
- Vinyl organic polymers. They are polymers whose main chain is formed exclusively by carbon atoms. For example: the polyethylene.
- Non-vinyl organic polymers. They are polymers that have carbon and oxygen and/or nitrogen atoms in their main chain. For example: the polyesters.
- inorganic polymers. They are polymers that do not have carbon atoms in their main chain. For example: the silicones.
According to its thermal behavior:
- thermosets. They are polymers that chemically decompose when their temperature rises. For example: the ebonite
- thermoplastics. They are polymers that can soften or melt when heated and then recover their properties when cooled. For example: the nylon.
- elastomers. They are polymers that can be easily manipulated and molded without losing their properties or structure. For example: rubber, silicone.
Examples of polymers
- RNA and DNA
- Vulcanized rubber