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polymerization, any process in which relatively small molecules, called monomers, combine chemically to produce a very large chainlike or network molecule, called a polymer. The monomer molecules may be all alike, or they may represent two, three, or more different compounds.
How does polymerization reaction take place?
When polymerization occurs, the smaller molecules which are known as monomers via chemical reaction are combined to form larger molecules. A collection of these large molecules form a polymer. The term polymer in general means “large molecules” with higher molecular mass. They are also referred to as macromolecules.
What are the 4 steps of polymerization?
Production Addition Polymerisation. Initiation. The polymerisation reaction is initiated through the addition of a free radical. Propagation. Following initiation, the process continues with the successive addition of monomer units to the chains. Termination.
What is polymerization explain with example?
A polymer is a large single chain-like molecule in which the repeating units derived from small molecules called monomers are bound together. The process by which monomers are transformed into a polymer is called polymerisation. For example ethylene polymerizes to form polyethylene.
How does addition polymerization work?
In addition polymerization (sometimes called chain-growth polymerization), a chain reaction adds new monomer units to the growing polymer molecule one at a time through double or triple bonds in the monomer. Chain initiation—usually by means of an initiator which starts the polymerization process.
What is released in the process of polymerization?
In condensation polymerization, water is released as a result of bonding between monomers, when one monomer gives up a hydroxyl group and the other monomer gives up a hydrogen in the process, forming a covalent bond between monomers to make a polymer.
What kind of reaction is occurring in polymerization?
Polymerization reactions are chain reactions, and the formation of Teflon from tetrafluoroethylene is one example. In this reaction, a peroxide (a compound in which two oxygen atoms are joined together by a single covalent bond) may be used as the initiator.
How do you initiate polymerization?
Initiation is the mechanism which starts the polymerization process. Vinyl monomers are quite easily polymerized by a variety of activating methods. Styrene, for example, can be converted to solid polymer simply by heating, and ultraviolet light can have exactly the same effect.
What are the methods of polymerization?
There are two basic types of polymerization, chain-reaction (or addition) and step-reaction (or condensation) polymerization. One of the most common types of polymer reactions is chain-reaction (addition) polymerization. This type of polymerization is a three step process involving two chemical entities.
What are the key stages of radical polymerization?
There are three general stages of free radical polymerization: 1) initiation, 2) propagation, 3) termination. Let’s consider these stages in the order which they occur.
How does RAFT polymerization work?
RAFT is a type of living polymerization involving a conventional radical polymerization which is mediated by a RAFT agent. Monomers must be capable of radical polymerization. There are a number of steps in a RAFT polymerization: initiation, pre-equilibrium, re-initiation, main equilibrium, propagation and termination.
How do you find addition polymerization?
Addition polymerization is the process of repeated addition of monomers that possess double or triple bonds to form polymers.Difference Between Addition And Condensation Polymerization. Addition Polymerization Condensation Polymerization Addition of monomers results in polymers Condensation of monomers result in polymers.
What are the physical stages of polymerization?
Longer chain- polymer dissolve slowly. Highly cross-linked – not dissolve.
What is degree of polymerization in chemistry?
The degree of polymerization, or DP, is the number of monomeric units in a macromolecule or polymer or oligomer molecule. The degree of polymerization or chain length is then 1000 by the first (IUPAC) definition, but 500 by the second.
What is polymerization of DNA?
Polymerization of Nucleotides (Phosphodiester Bonds) Nucleotides are joined together similarly to other biological molecules, by a condensation reaction that releases a small, stable molecule. The 3′ hydroxyl group forms a bond to the phosphorus atom of the free nucleotide closest to the 5′ oxygen atom.
What is chain reaction polymerization?
3.02. A ‘chain polymerization’ is a chain reaction in which the growth of a polymer chain proceeds exclusively by reaction(s) between monomer(s) and active site(s) on the polymer chain with the regeneration of the active site(s) at the end of each growth step.
What does a polymerization reaction do Milady?
Also known as polymerization reaction; process that joins together monomers to create very long polymer chains. Substance formed by combining many small molecules (monomers) into very long chain-like structures. polymerization. Also known as curing or hardening; chemical reaction that creates polymers.
How do you terminate polymerization?
With step-growth polymerization, the reaction can be terminated by adding a monofunctional species containing the same functionality as one or more of the types of monomer used in the reaction.
What molecules can initiate polymerization?
Initiate Polymerization Polymerization. Cross-Link (Molecular Structure) Hydrogen. Monomers. Oligomers. Photoinitiator. Polymer Chain.
How does emulsion polymerization work?
Emulsion polymerization is a polymerization process with different applications on the industrial and academic scale. It involves application of emulsifier to emulsify hydrophobic polymers through aqueous phase by amphipathic emulsifier, then generation of free radicals with either a water or oil soluble initiators.
Why do we polymerize?
A basic understanding of polymerization processes is important not only because polymerization affects structure, and hence properties, but also because some processing routes can convert monomers directly to a finished shape. They offer manufacturing industry considerable benefits both in direct and indirect costs.
Is polymerization reversible?
Reversible polymerization typically involves two steps, including (i) forward polymerization, which converts small monomers into macromolecule; and (ii) depolymerization, which is capable of regenerating original monomers. Furthermore, recycled monomers can be repolymerized into new polymers.
How does radical polymerization work?
Free-radical polymerization (FRP) is a method of polymerization, by which a polymer forms by the successive addition of free-radical building blocks. Free radicals can be formed by a number of different mechanisms, usually involving separate initiator molecules.
How does oxygen inhibit polymerization?
The presence of oxygen is known to inhibit radical polymerization by reacting with the active radicals and generating dead chain ends.
What is chain initiation step?
The initiation step in a radical chain reaction is the step in which a free radical is first produced. A termination step of a radical chain reaction is one in which two radicals react together in some way so that the chain can no longer be propagated.
