Question

Formulation of nylons and polyesters are called step growth polymerisation because:
A.the polymers are formed by adding a monomer step by step
B.the polymers are formed by condensation and monomers are joined by loss of simple molecules like water
C.the monomers used for condensation are unsaturated molecules
D.the polymers are formed by addition of a large number of free radicals formed by monomers

Answer 1

Hint: Step growth polymers are the ones in which monomers are joined together to form first dimer and then a trimer, then oligomer and finally a polymer.

Complete step by step answer:
Let’s start discussing polymerisation, polymerisation is a process in which the large number of monomers combine together to form a polymer or a three dimension network. There are many types of polymerization and different systems to classify them. The polythene that we usually see is also a polymerised product.
Now, coming back to the question, here we are talking about nylons and polyesters, which are generally called step growth polymers. So, first define the step growth polymer. Step growth polymers are the ones in which monomers are joined together to form first dimer and then a trimer, then oligomer and finally a polymer. Many natural and synthetic polymers are being formed using this method.
In case of nylons and polyesters, its molecules lose simple molecules like water and then the polymer is formed by the condensation.
So, the answer to this question is option B. the polymers are formed by condensation and monomers are joined by loss of simple molecules like water.

Note:
Step growth polymerisation is used for the formation of polymers like polyuria, polyamide (nylon), polyurethane, polyether, etc. All these polymers are having different properties than their monomers, dimers, oligomers. Step growth polymerization does not require any initiator and the end remains active.