Question

28 Bakelite, a durable plastic used for the casing of early radios and TVs, was the first of the thermosetting polymers. It is a highly cross-linked polymer formed from the acid-catalyzed polymerization of phenol and formaldehyde. Because it is much darker than Melmac, Bakelite's range of colors is limited. Propose a structure for Bakelite. a. Draw the structure of a short segment of PHB. b. Draw the structure of a short segment of PHBV with alternating monomers.

Answer 1

The mechanism of formation of Bakelite is shown:

HO Repeat oH OH OH OH HO CH 2 오 ド:CHossa linked Bakelite

Phenol is allowed to react with three moles of formaldehyde which gives 2,4,6-tris(hydroxymethyl)phenol. Which is heated and treated with phenol to give monomer of bakelite, repeating the process several times will give Cross-linked Bakelite.

The structures are:-

2. cH 3 Shot Seqment PHBV

hope this helps!