Question

The monomers of BUNA-S rubber are:
A. Vinyl chloride and sulphur
B. Butadiene
C. Styrene and butadiene
D. Isoprene and Butadiene

Answer 1

Hint: BUNA-S is a copolymer containing two different monomeric units in its structure. It is a synthetic rubber prepared by using sodium as a reagent. BUNA-S comes under rubber due to its chemical and physical properties.

Complete step by step answer:
- In the question it is given that what are the monomers of the BUNA-S rubber.
- We have to write the monomeric units of the BUNA-S copolymer.
- The name BUNA-S itself reveals the monomers present in it.
- BU - stands for Butadiene, S- stands for Styrene, NA-stands for sodium.
- Means the monomeric units present in BUNA-S are butadiene and styrene.
- The structures of the butadiene and styrene are as follows.

- The preparation of BUNA-S rubber from butadiene and styrene is as follows.

- In the above preparation, n moles of butadiene react with n moles of styrene and form the polymer BUNA-S as the product.
- Therefore BUNA-S contains Styrene and butadiene as monomeric units.

- So, the correct option is C.

Additional information:
- Due to its properties it competes with natural rubber.
- BUNA-S is mostly used in coating papers.
- It is a cost-effective resin.
- It is used in sealing as a binding agent and it is an alternative for PVA (poly vinyl alcohol).

Note: BUNA-S is going to form from its monomeric units (Styrene and butadiene) through addition polymerization reaction in the presence of Sodium. It is not a natural rubber, it is a synthetic rubber.