Chain Polymerization Mechanism

First of all, we learn about the basis of Polymerization techniques;
"Polymerization technique is defined as the fundamental process by which low molecular weight compounds (Monomers) are converted into high molecular weight compounds (means, polymers)". There are several polymerisation techniques are available but most of the polymerization techniques fall under two categories: Addition polymerization and Condensation polymerization

The mechanism of chain polymerization reaction or the chemical reaction (or other process) is the reaction in which the products themselves promote or spread the reaction. In this, reactive product or by-product causes additional reactions to take place. 
(A series of events so related to each other that each one initiates the next) 
This chain polymerization mechanism occurs in three basic steps;
1) Chain Initiation
2) Chain Propagation
3) Chain Termination

1) Chain initiation –
It is the first step in the chain-growth polymerization process that is required to initiate polymer chain growth. In this, first the initiator is converted into intermediate with the help of light, heat or catalyst. These intermediates can be atoms, ions, molecules or fragments of molecules. These initiators may be monofunctional or multifunctional or may be unsaturated in nature.
2) Chain propagation
Once a reactive intermediate is generated, it can react with other stable molecules to form new reactive intermediates. Propagation step involves the formation of new intermediate molecules or atoms or ions, etc.
3)Chain termination
In this step, all the intermediates generated from the first two steps disappear and no intermediate remains. Hence, termination lowers the concentration of intermediates from the system.


Hope you have found this article helpful!!
Do you have suggestions? Please write in comment box!!!
Feel free to comment if you have any queries!!

Comments

Post a Comment

Most Viewed Posts

Zeroth Law Of Thermodynamic: The Thermal Equilibrium Law

Image
In thermodynamics, we will see two types of walls. One is the Diathermic wall and the other is the adiabatic wall. Let us now go through them one by one.  • So the first is the Diathermic wall- " A Diathermic wall is a wall that allows the easy exchange of heat between two bodies (or between two systems or between system and surrounding) but does not allow the exchange of mass between them ". This means that it is a good conductor of heat. It is sometimes called as metallic wall because it is made of metal. • While the other is the adiabatic wall- " An Adiabatic wall is that wall which neither allows exchange of heat nor mass between two systems (or between system and surrounding) ". Since there is no exchange of heat and mass between the system and its surroundings, the system remains insulated from its surroundings. ➛ That's why whenever we separate the two systems by an adiabatic wall, then there is no concept of equilibrium between them. But whenever we sep...
Read more

Characteristics Of Entropy

Image
Entropy is an intrinsic property of a substance and is not affected by the external position of a system or its motion relative to other systems. It is a measure of the randomness of the system. Thus, the higher the randomness of the system, the higher the entropy of the system and the lower the randomness of the system, the lower the entropy of that system. Entropy   " Entropy is defined as a measure of the system's thermal energy that is incapable of doing work ". It is a state function.  For Example Heat is a form of energy that is incapable of doing work. Therefore, the more heat added to the system (or tranfer from the system), the higher (or the lower) will be its entropy.  The formula for change in entropy is given by the equation;                      ➩ ∆S = ∆Q/T For a reversible process, the change in entropy is given as; The Total Change In Entropy Entropy change is zero at equilibrium condition or whenev...
Read more

Reversed Carnot Cycle

Image
We have already discussed the concept of “ Carnot Cycle ”   & “ Its Efficiency ” and we have also seen the concept of “ Carnot Theorem And Its Explanation ” in our previous post. As we have already discussed that the Carnot Cycle is a reversible cycle and every process in the Carnot cycle is a reversible process. Therefore, every process of the Carnot cycle can be reversed. And the cycle can be operated in the opposite direction as well. In this article, we're interested in learning more about the reversed Carnot cycle, also known as the reversed Carnot heat engine cycle. Reversed Carnot Heat Engine It is important to note that if a reversible process is reversed, all related energy types—such as heat energy or work energy—will have the same magnitude but the direction of their interaction with matter will be changed. Let us first look at the Reverse Carnot Heat Engine  cycle here; The reversed Carnot heat engine cycle is depicted in the following figure. According to the...
Read more