Question

How many of the following polymers given, come under the category of condensation polymers? Bakelite, Teflon, Nylon 6, Dacron, Polyisoprene, Melamine, Neoprene

• A. 4
• B. 3
• C. 5
• D. 6

Answer 1

Answer: (A)

The given polymers are formed as follows :

Bakelite These are made by the condensation reaction of formaldehyde and phenol in presence of either an acid or base, as a catalyst. It involves the formation of methylene bridges in ortho/ para position





On heating with formaldehyde, novolac undergoes cross - linking to form an infusible solid mass, which is known as bakelite.



It is a condensation polymer.

Teflon It is prepared by heating tetrafluoroethylene at high pressure in the presence of peroxides or ammonium peroxo sulphate $\left[{\left(N{H}_4\right)}_2{S}_2{O}_8\right]$ catalyst.

It is chemically inert and resistant to attack.

$\underset{\text{Tetrafluroethene}}{nC{F}_2=C{F}_2}\underset{\text{High pressure}}{\overset{\mathrm{n}(\mathrm{NH}{}_4){}_2\mathrm{S}{}_2\mathrm{O}{}_8}{\to }}\underset{\text{Teflon}}{-(C{F}_2-C{F}_2{)}_n-}$

It is an addition polymer.

Nylon-$6$ or Perlon It is also known as perlon and is obtained from the monomer caprolactum. This caprolactum is obtained from cyclohexane.



Here, in both monomeric species, there are $6$ carbon atoms each.

Dacron or Terylene It is a polymer obtained by condensation reaction between ethylene glycol and terephthalic acid at $425-475K$ in the presence of zinc acetate antimony trioxide catalyst.



Nylon -$6$ and dacron both are condensation polymers.

Polyisoprene



It also an addition polymer.

Melamine In this particular reaction, melamine and formaldehyde copolymerise to give another polymer



Thus, is a condensation polymer.

Neoprene It is also called polychloroprene and formed by the free radial polymerisation of chloroprene and has superior resistance to vegetable and mineral oils.

$\underset{\text{Chloroprene}}{nC{H}_2=\stackrel{\underset{|}{C}l}{C}-CH=C{H}_2}\stackrel{\text{Polymerisation}}{\to }\underset{\text{Neoprene}}{-{\left[C{H}_2-\stackrel{\underset{|}{C}l}{C}=C{H}_2-C{H}_2\right]}_n-}$

It is an addition polymer.

Hence, among the given polymers, we have four (4) condensation-polymers