Question

Identify ureaformaldehyde resin from following polymers?

• A.

  

• B.

  

• C. \([\text{NH}-\text{CO}-\text{NH}-\text{CH}_2]_n\)
• D. \([\text{NH}-(\text{CH}_2)_5-\text{CO}]_n\)

Hint:

Urea-formaldehyde resin repeats the unit NH-CO-NH-CH2.

Answer 1

The Correct Option is C

Step 1: Monomers:
Urea contributes NH-CO-NH and formaldehyde contributes CH$_2$. Joining them with loss of water gives the unit NH-CO-NH-CH$_2$.

Step 2: Rule Out:
The pictured chains in (A) and (B) have C-C backbones with side groups (amide and phenyl), typical of addition polymers. Option (D) is the polyamide nylon-6.

Step 3: Answer:
Option (C).

Final Answer:
Option (C). \[ \boxed{\text{(C) } [\text{NH-CO-NH-CH}_2]_n} \]