Question

1. Could Carothers have produced strong polyester fibers by (a)ester interchange or (b)Schotten– Baumann reactions using aliphatic reactants?
2. Which would be useful as a fiber: (a) poly(ethylene terephthalate) or (b) poly(hexylene terephthalate)?
3. In which reaction would you expect the more “wasted loop”: the reaction of oxalyl chloride with (a) ethylenediamine or (b) 1,6-hexanediamine? 

4. Which would be the better or stronger fiber: one made from an ester of (a) terephthalic acid 
or (b) phthalic acid? 

5. Which would be more flexible: (a) poly(butylene terephthalate) or (b) poly(hexylene 
terephthalate)? 

6. Which would be higher melting: (a) a polyamine or (b) a polyester with similar members of 
methylene groups in the repeat unit? 

7. Which of the following could be a non-petrochemical plastic: (a) Bakelite, (b) urea plastics, or 
(c) melamine plastics? 


Answer 1

Solution:

Part A) The carothers synthesized soft poly esters by exchange of ester groups. They did not synthesized strong polyesters.

B) Polyethylene terephthalate

It is a soft polymers, hence useful in fiber.

C) Ethylenediamine

Ethylenediamine forms more wasted loop when reacts with oxalyl chloride because it can form six membered ring.

D) Terepthalic acid

Terepthalic acid forms better and stronger fiber because it has more stable geometry.

E) Polyhexylene terephthalate

It forms more flexible polymer.