Question

Which among the following is a step growth polymer?
A. PTFE
B. PVC
C. Polyester
D. Polythene

Answer 1

Hint: A step growth polymer has brunched units. It is formed by the reaction of two different monomer units where some side products like water, ammonia gas etc are produced. It involves condensation reactions.

Complete step by step solution:
Polymers are formed by the addition of two or more monomers. The polymers can be classified into various categories but according to the mode of polymerization it can be classified into two main classes. One is an additional polymer, another one is a condensation polymer. In addition, the same monomer is used by an additional reaction to form a linear polymer. It is called a chain growth polymer.

PVC is a linear polymer of vinyl chloride. It is prepared by a chain reaction. Polyethylene is a linear polymer of ethylene or ethene. It is prepared by a chain reaction. Teflon is a linear polymer of tetrafluoroethylene. It is also called polytetrafluoroethylene. It is prepared by a chain reaction.

In condensation polymerization two different monomers are used and some side products are formed. It is step growth polymerization. Polyester is a polymer of ethylene glycol and terephthalic acid. Thus it is a step growth polymer.
Thus the correct option is C.

Note: The step growth polymerization reaction takes place between the functional groups of two monomer units. So, that’s why this reaction takes place in steps. Some step growth polymers are Nylon 6,6, Nylon-2,6 etc.