Question

Explain the difference between Buna-N and Buna-S.

Answer 1

Hint: Polymers are substances containing a large number of structural units joined by the same type of linkage. Polymers in the natural world have been around since the beginning of time. Starch, cellulose, and rubber all possess polymeric properties. 

Complete step by step answer:
Let us understand a bit more about polymers.
Polymers are high molecular weight compounds whose structures are made up of a large number of simple repeating units. The repeating units are usually obtained from low molecular weight simple compounds referred to as monomers. The process by which monomers are converted into Polymers is called polymerisation.

Let us differentiate between Buna-N and Buna-S:

Buna-N	Buna-S
It is a copolymer of 1, 3-Butadiene and acrylonitrile.It is also known as Nitrile-Butadiene-Rubber. The amount of acrylonitrile is determined by the oil resistance, as the cyanide ion in the acryl group enhances the oil and solvent resistance. Used for making synthetic leather, footwear and is also used in seals, belts, oil seals, etc.	It is formed by copolymerization of 1, 3-Butadiene and styrene.It is also called Styrene-Butadiene Rubber.It has slightly less tensile strength than natural rubber. Used for making automobile tyres and rubber soles. It is also used to make inner tubes for engines, bubble gums, etc.

Note: Generally, you should know that Buna-N have poor resistance to ozone, sunlight and the reason for this is due to the presence of double bonds present in the polybutadiene segment and Buna-N can generally withstand a range of -40 to 108 degree C temperature.