What Is Polymerization?
The chemical process in which lower molecular weight substances [monomers] are bond together to form high molecular weight substances [polymers] is known as polymerization.
Why Polymerization?
Polymers [products of the polymerization process] offer lots of extensive properties as compared to the other natural or synthetic products. These extensive properties of polymers include:
- Higher strength
- Resistance to corrosion
- Easy to fabricate - Can be molded in any shape, size and color
- Improved performance
- Reduced product costs
- Reduced weight [because of improved ratio of strength to stiffness]
- Most of them are good electrical insulators [such as plastics]; However some are good electrical conductors too [carbon black mixed polymers].
Degree Of Polymerization:
Degree of polymerization refers to the number of monomers in polymer molecules. This degree of polymerization is directly related to the polymer properties, such as melting point, mechanical strength, etc.
For homopolymers , degree of polymerization can be calculated as:
[latex size=0 color=000000 background=ffffff]\displaystyle X_{n} = \frac{M_{n}}{M_{o}} [/latex]
Where,
[latex size=0 color=000000 background=ffffff]\displaystyle X_{n} [/latex] = Degree of polymerization
[latex size=0 color=000000 background=ffffff]\displaystyle M_{n} [/latex] = Total molecular wt. of Polymer
[latex size=0 color=000000 background=ffffff]\displaystyle M_{o} [/latex] = Molecular wt. of Polymer unit
Mechanisms Of Polymerization:
Polymerization processes or mechanisms of polymerization can be divided into two groups:
- Condensation polymerization [or step growth polymerization]
- Addition polymerization [or Chain growth Polymerization]
Types Of Polymerization
Polymerization process requires quantity of monomers along with the initiator or catalyst to start the reaction. Polymerization processes can be classified in terms of the reaction mediums; i.e.
- Bulk polymerization
- Solution polymerization
- Suspension polymerization
- Slurry polymerization
