Question

Which of the one is copolymer?
A. Styrene butadiene rubber
B. Polythene
C. Nylon
D. None of the above

Answer 1

Hint: Copolymer has more than one type of repeating unit (i.e. the monomer unit). Try to figure out the monomer units of each polymer given in the question.

Complete answer:
When a large number of molecules (usually referred as monomer units) join in a manner to form a long structure, the structure formed is known as a polymer. In a polymer, a molecule or monomeric unit repeats again and again that’s why the formed structure is called as a polymer as we know ‘poly’ means many and ‘mer’ means units.’
The units that repeat are referred to as the repeating units or monomers. Based on the type of polymer units the polymer is divided into two categories that are, homopolymer and copolymer.
When more than one type of repeating unit is present in a polymer, the polymer is known as copolymer.
- The styrene butadiene rubber is made up of two different types of monomer, styrene and butadiene. It can be referred to as a copolymer.
- Polythene is formed by polymerization of monomer unit ethylene. It is not a copolymer as it has only a single repeating unit.
- Nylon is not a single substance but the name is used for a whole family of the same materials called as polyamides. Some of the groups from its family are copolymers. For example, $Nylon-6,6$. So, we cannot say that nylon is actually a copolymer.

Hence, the correct option is A.

Note: The polymer polythene is referred to as a homopolymer. The name of the homopolymer includes the name of the monomer unit from which the polymer is derived and the prefix ‘poly’.