Basic-Gyan

" A polymers is defined as a large molecule (or macromolecule), formed by joining together thousands of smaller molecule units by chemical bonds ". These smaller molecules that interact with each other to form a larger molecule are called " Monomers ".   And in polymer chemistry, a reaction by which smaller molecules (called monomers) react with each other to form a larger molecule (called polymers), is called " Polymerization ".  Polymers are the high molecular mass compounds.   We know that a polymer can be formed from only one type of monomer unit or from two or more than two different types of monomer units.  Based on that, there are two types of polymerization techniques; namely Homopolymerization reaction and Copolymerization reaction. (In my previous posts, we have seen two types of polymerization techniques, namely chain-growth polymerization reaction and step-growth polymerization reaction classified on the basis of saturated or unsaturated monom

" Ionic polymerization is defined as a type of addition polymerization in which the active centres (or intermediates) are ions or ion pairs ". It can be considered as an alternative to free radical polymerization. Cationic polymerization reaction is one of two processes of Ionic polymerization to convert a monomer molecule into a polymer.  " Cationic polymerization is defined as a type of addition ionic polymerization in which the active centres are cations (or positive ions) ".  In this, the cationic initiator is used to transfer the positive charge onto the monomer molecule so that it becomes reactive. This reactive monomer reacts with other monomer molecules to form a polymer in the same way that a free radical does.  Examples of polymers formed by Cationic polymerization are Poly-isobutylene (PIB), Poly-butene and Butyl rubber, etc. The types of monomers required for cationic polymerization are limited to " alkanes " with " electron donating subst

First of all we should know, What is Kinetic Chain Length? And why do we need it? After that, we will know what the kinetic chain length will be for the various addition polymerization processes. Let us first see what is the length of the kinetic chain. Kinetic chain length – The kinetic chain length of a polymer, in polymer chemistry, is the average number of units called monomers added to a growing polymer chain during chain-growth polymerization.                                          OR The kinetic chain length of a polymer is defined as the average number of monomer units that react with active centers such as radicals, ions, etc, from the initiation phase to the termination phase.  Mathematical definition , The kinetic chain length of a polymer is equal to the rate of the overall polymerization reaction divided by the rate of the initiation step in which the chain carriers are formed. Thus, The kinetic chain length is a more general development of the average degree of polymeri

" Ionic polymerization is defined as a type of addition polymerization in which the active centres (or intermediates) are ions or ion pairs ". It can be considered as an alternative to free radical polymerization. Anionic polymerization reaction is one of two processes of Ionic polymerization to convert a monomer molecule into a polymer. " Anionic polymerization is defined as a type of addition ionic polymerization in which the active centres are anions (or negative ions) ". In this, the anionic initiator is used to transfer the negative charge onto the monomer molecule so that it becomes reactive. This reactive monomer (or monomer anion) reacts with other monomer molecules to form a polymer in the same way that a free radical or cationic polymerization does. Examples of polymers formed by anionic polymerization are Synthetic Polybutadiene rubber, styrene butadiene rubber (SBR), Thermoplastic Styrene elastomer, etc.                  The monomer molecules used in ion

" Chain-growth polymerization or addition polymerization reaction is a polymerization technique where unsaturated monomer (means containing double and triple bonds in their molecular formula) molecules add onto the active site on a growing polymer chain one at a time ".  Since, we know that  d epending on this active site present on the growing polymer chain, there are three types of addition polymerization:  free radical polymerization, ionic polymerization, and coordination polymerization.  Free radical polymerization is one of those types of additional polymerization in which the active site is free radical. In this, initiators are used to generate free radicals. Free radical is denoted as "M•".  ➛ Initiator molecules are of the following types; (a) Thermal initiators (such as peroxides, azo-compounds) (b) Photochemical initiators (such as Disulfides, ketones, Azo, Peroxides,etc.) (c) Redox initiators (such as Fenton reagent) (d) Ionising initiators ( such a

" Polymerization technique is defined as the fundamental process by which low molecular weight compounds are converted into high molecular weight compounds (means, polymers) ".             " Chain-growth polymerization reaction " also known as " Addition polymerization reaction ". In this polymerization reactions, monomer molecules bond to each other to form a larger molecule called a polymer, without removing any of the smaller molecules as a byproduct. An addition polymer is a very long organic molecule formed as a result of an addition reaction between monomers with unsaturated carbon-carbon bonds.  ☛ The kinetics of addition polymerization proceeds according to the chain polymerization mechanism that occurs in three basic steps; 1) Chain initiation 2) Chain propagation 3) Chain termination Since, addition polymerization occurs in four ways (free radical/cationic/anionic/co-ordination Polymerization) therefore all its types follow the same kinetic behav