Question

Which one of the polymers does not contain \(-COO-\) linkage in its structure?

• A. Bakelite
• B. Glyptal
• C. PHBV
• D. Dacron

Hint:

Bakelite is a phenol-formaldehyde thermosetting polymer, whereas Glyptal, PHBV, and Dacron are polyesters.

Answer 1

The Correct Option is A

Step 1: Identify the linkage asked.
The $-COO-$ group is an ester linkage. Polyesters contain this group in their repeating units. We must find the polymer that does NOT have it.
Step 2: Check Glyptal.
Glyptal is made from glycerol and phthalic acid and is a polyester. So it contains ester $-COO-$ linkages.
Step 3: Check PHBV.
PHBV is a biodegradable polyester. So it also contains ester linkages.
Step 4: Check Dacron.
Dacron, also called PET, is a polyester made from ethylene glycol and terephthalic acid. So it contains ester linkages too.
Step 5: Check Bakelite.
Bakelite is a phenol-formaldehyde resin. Its chains are joined by methylene bridges $-CH_2-$, not ester groups. So it has no $-COO-$ linkage.
Step 6: State the answer.
The polymer without the ester linkage is \[ \boxed{\text{Bakelite}} \]