Polymerization and Types

Image

                                    

Polymerization:

They are huge chains or sometimes even 3D structures of repeating units known as monomers. The monomer is the basic unit of a polymer. These monomers can bond to each other on each side, potentially forever.

So this reaction of combining these monomers to form long chains or three-dimensional networks is known as polymerization. Broadly polymerization can be classified into two categories,

• Step-Growth or Condensation Polymerization

•Chain-Growth or Addition Polymerization

Addition Polymerization

As the name suggests addition polymers form when an addition reaction occurs. The repeating monomers form a linear or branch structure depending on the type of monomer. During addition polymerization, the monomers rearrange themselves to form a new structure. But there is no loss of an atom or a molecule. Again there are four types of addition polymerizations which are

Free Radical Polymerization: Here the addition polymer forms by addition of atoms with a free electron in its valence shells. These are known as free radicals. They join in a successive chain during free radical polymerization.

Cationic polymerization: A polymerization where a cation is formed causing a chain reaction. It results in forming a long chain of repeating monomers

Anionic Vinyl Polymerization: Involves the polymerization of particularly vinyl polymers with a strong electronegative group to form a chain reaction’

Coordination Polymerization: This method was invented by two scientists Ziegler and Natta who won a Nobel Prize for their work. They developed a catalyst which let us control the free radical polymerization. It produces a polymer which has more density and strength.

Condensation Polymerization

Condensation polymers form from the step growth polymerization. Here when molecules of monomers react to form a bond they replace certain molecules. These molecules are the by-product of the reaction. In most cases, this by-product is a water molecule.

The type of polymers that result from a condensation polymerization depends on the monomers. If the monomer has only one reactive group, the polymers that form have low molecular weight. When monomers have two reactive end groups we get linear polymers and monomers with higher than two reactive groups results in a polymer with a three-dimensional network.

Polyester and nylon are two common condensation polymers. Even Proteins and Carbohydrates are a result of condensation polymerization..

 

Warm Regards,
Jessie
Journal Manager
Journal of Bioremediation & Biodegradation