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1800-102-2727Can you guess why you don't get an electric shock when you unintentionally or intentionally switch on the fan in your home?
Electric switches though help in the conduction of electricity from one source to another still it is generally safe when touched with a naked hand.
But do you know which insulating material is used for making electric switches?
A material that does not conduct electricity is known as an insulator. Nonmetal is an excellent insulator, and the insulator that protects us from getting electric shock is a polymer known as bakelite formed by the step-growth polymerization technique in which the smaller molecules which are also known as monomers react with each other to form larger structural units known as polymers, releasing also small by-product molecules. Polymer formation or polymerization process can take place in many ways. Let us learn in this article about the polymer formed by what is called condensation method..

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Polymerization is generally defined as a chemical reaction between many molecules of the same or different substance called monomers that results in the formation of either a long linear polymer chains or three-dimensional networks. Polymerization is typically accomplished through a variety of reaction mechanisms that are influenced by factors such as the functional groups of the reacting compounds and their non-bonding interactions.
Condensation polymers are created through a step-growth polymerization technique in which smaller molecules or monomers react with one another to form larger structural units (called polymers) while releasing a small by-product molecule like water. Condensate is the common name for the by-products.
Two bifunctional monomers condense to form dimers, which then form tetramers, and so on, with the loss of simple molecules such as H2O, CO2 and HCl in the process.
Examples of Condensation Polymer With Monomers
Terylene:
It is a polymer produced by polymerizing ethylene glycol [OH-(CH2)2-OH] and terephthalic acid [HOOC - C6H4 - COOH].

Nylon-6,6:
Nylon-6,6 is produced by the condensation polymerisation of hexamethylenediamine and adipic acid.

Glyptal:

Nylon-6,10:
Nylon-6,10 is produced by the condensation polymerisation of hexamethylenediamine and sebacic acid.

Nylon-6:
Nylon-6 is produced by heating caprolactam at temperatures ranging from 533 K to 543 K. Nylon-6 is also known as Perlon-L.

Melmac:

Bakelite:
It is a condensation polymer constituted from the monomers of phenol and formaldehyde.

Polyurethanes:


Novolac or Resol:

Q1. The monomer required for the formation of bakelite is_________.
Answer:(B)
Solution: Glyptal is produced by the condensation polymerisation of phthalic acid and ethylene glycol. Nylon-6 is produced by heating caprolactam at temperatures ranging from 533 K to 543 K. Nylon-6 is also known as Perlon-L. Terylene is a polymer produced by polymerizing ethylene glycol and terephthalic acid. Bakelite is a condensation polymer constituted from the monomers of phenol and formaldehyde. Polyoxybenzyl methylene glycol anhydride is another name for bakelite. Therefore, option (B) is correct.
Q2. Which of the following option is correct with respect to the condensation polymer?
Answer:(D)
Solution: Condensation polymers are formed through a step-growth polymerization technique in which monomers with one reactive group are combined, the average molecular weight decreases in condensation polymerisation. Two bifunctional monomers condense to form dimers, which then form tetramers, and so on, with the loss of simple molecules such as H2O, CO2 and HCl in the process.
Q3. The monomer required for the formation of terylene is_________.
Answer: (D)
Solution: Glyptal is produced by the condensation polymerisation of phthalic acid and ethylene glycol. Melmac is produced by polymerising melamine and formaldehyde. Nylon-6 is produced by heating caprolactam at temperatures ranging from 533 K to 543 K. Nylon-6 is also known as Perlon-L. Terylene is a polymer produced by polymerizing ethylene glycol [OH-(CH2)2-OH] and terephthalic acid [HOOC - C6H4 - COOH]. Therefore, option(D) is correct.
Q4. List some important use of the polymers formed by the condensation polymerisation method.
Answer: Some important use of the condensation polymers are:
Q1. What is the difference between condensation polymerisation and addition polymerisation?
Answer: In addition polymerisation, molecules of the same or different monomers add on to one another, resulting in the formation of a macromolecule. The repeating unit of the polymer has the same molecular formula as the parent monomers. For examples, polyethene, polyacrylonitrile (PAN), buna-S, buna-N, and so on. Whereas in condensation polymerisation, monomers combine with the loss of simple molecules such as water, carbon dioxide, ammonia, and so on to form a macromolecule. The repeating unit of the polymer has a different molecular formula than the parent monomers.
Dacron, Nylon-6, Nylon-6,6 etc are some examples of condensation polymers.
Q2. What is step growth polymerisation?
Answer: Step-growth polymerisation is a polymerization method in which bi-functional or multifunctional monomers react to produce dimers, trimers, longer oligomers, and finally long-chain polymers in stepwise manner. Many are found naturally and some synthetic polymers, such as polyesters, polyamides, and polyurethanes, are generated by step-growth polymerisation.
Q3. Why bakelite is also classified as thermosetting plastics?
Answer: Thermosetting polymers are low molecular weight polymers that, when heated in a mold cavity, change chemical composition to form a hard, infusible, and insoluble mass. The hardening is caused by extensive cross-linking of the polymers. Bakelite is an example of a thermosetting polymer because when bakelite is formed from the cross-linking of phenol and formaldehyde and once the polymer is formed it becomes hard and cannot be remolded.
Q4. What is the difference between thermosetting plastics and thermoplastics?
Answer: These are low molecular weight polymers that, when heated in a mold cavity, change the chemical composition to form a hard, infusible, and insoluble mass. The hardening is caused by extensive cross-linking of the polymers.
Intermolecular forces exist between elastomers and fibers in thermoplastics. These are linear polymers that are hard at room temperature but soften and become viscous when heated. They become rigid again after cooling. The heating and cooling processes can be repeated as many times as necessary without affecting the chemical composition or mechanical properties.