What are synthetic rubber ? Explain the preparation and uses of the following
i) Neoprene ii) Buna -N iii) Buna -S

Explanation

The polymer which is capable of getting stretched almost to double the length and which is also vucanizable as in the case of natural rubber is called a synthetic rubber .
1) These are homo polymers of 1,3-butadiene derivatives (or) copolymers in which one of the monomer is 1,3 Butadiene (or) its derivatives and the other is any unsaturated monomer .
2) Synthetic rubber retune to its original shape and size when the stretched force is removed
E.g : Neoprene : Neoprene is formed by the free radical polymerisation of chloroprene (2-chloro 1,3 -Butadiene )
`{:(n"("CH_(2)=overset(Cl)overset(|)C-CH=CH_(2)")"overset"Polymerisation"to"("--CH_(2) overset(Cl)overset(|)C=CH-CH_(2)--")"_n),("Chloroprene"" " " Neoprene"),("2-chloro 1,3 -Butadiene"):}`
Uses:
1) It has superior resistance to vegetable and animal oils.
2) It is used in the manufacture of gaskets , conveyir belts.
ii) Buna -N : Buna -N is the copolymer which is formed by the polymerisation of 1,3 Butadiene and acrylonitrile. `{:(n(CH_2=CH-CH=CH_2)+n(CH_2=CH-CN)rarr"("-CH_2-CH=CH-CH_2-CH_2CH_2-overset(N)overset(|)CH-")"_n),( "1,3 Butadiene "" Acrylonitrile " "Buna -N"):}`
Uses :
1) It is resistant to the action of petrol ,lubricating oil and organic solvents.
2) It is used in making oil seals, tank linling .
iii) Buna -S : Buna -S is the copolymer which is formed by the polymerisation of 1,3 Butadiene and Synrene.
`{:(n(CH_2=CH=CH_2)+n(CH_2=CH-C_6H_5)rarr"("-CH_2-CH=CH-CH_2-CH_2-overset(C_6H_5)overset(|)CH-")"_n),(" ""1,3 -Butadiene "" Styrene"" Buna-S"):}`
1) It is a good substitute for natural rubber.
2) It is used in manufacture of auto types.
3) it is used in manufacture of floor tiles .
4) it is used in manufacture of foot wear components , cable insultation