Phenol and formaldehyde undergo condensation to give a polymer (A) which on heating with formaldehyde gives a thermosetting polymer (B). Name the polymers. Write the reactions involved in the formation of (A). What is the structural difference between the two polymers?


 

Phenol and formaldehyde undergo condensation to give a polymer novolac (A) which on heating with formaldehyde gives bakelite (B) as a thermosetting polymer.

The sequence of the reaction can be written as

The structural difference between these two is that novolac is a linear polymer while bakelite is a cross-linked polymer.