Question

Which of the following polymers, need atleast one diene monomer for their preparation?

(i) Dacron

(ii) Buna-S

(iii) Neoprene

(iv) Novolac

Answer 1

(ii) Buna-S

(iii) Neoprene

Explanation:

\[\begin{array}{cc}\phantom{}
\phantom{..................................................................}\ce{C6H5}\\
\phantom{...............................................................}|\\
\ce{\underset{1, 3-Butadiene}{nCH2 = CH} - CH = CH2 + n C6\underset{Styrene}{H5CHCH2} -> \underset{(Buna - S)}{\underset{Butadiene-styrene copolymer}{-(CH2 - CH = CH - CH2 - CH - CH2)\underset{n}{-}}}}
\end{array}\]

Neoprene or polychloroprene is formed by the free radical polymerisation of chloroprene.

\[\begin{array}{cc}
\phantom{..}\ce{Cl}\phantom{...................................}\ce{Cl}\phantom{.........}\\
\phantom{}|\phantom{.....................................}|\phantom{........}\\
\ce{\underset{2-Chloro-1, 3-buta-1, 3-diene}{\underset{Chloroprene}{n CH2 = C - CH = CH2}} ->[Polymerisation] \underset{Neoprene}{-[CH2 - C = CH - CH2]\underset{n}{-}}}
\end{array}\]