question_answer 81)

  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 two polymers?

Answer:

                  'A' is novolac and 'B' is bakelite. For reactions involved and structural differences, refer to sec. 15.6.4, pages 15/14-15/15.