Question

On mercerization, the strength and moisture absorption capacity of cotton fibre increases. The reason for increase is

• A. decrease in orientation and decrease in amorphous region
• B. increase in orientation and decrease in amorphous region
• C. increase in orientation and increase in amorphous region
• D. decrease in orientation and increase in amorphous region

Hint:

Mercerized cotton is preferred for bright colors because the increased amorphous region allows more dye to settle deep within the fiber.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:

• On mercerization of cotton, strength and moisture absorption both increase. We must find the reason.

Step 2: Detailed Explanation:

• Mercerization (swelling in NaOH) converts the fibre cross-section from kidney shape to nearly circular and removes convolutions, which improves molecular orientation and hence strength.

• Swelling also disrupts the crystalline structure (cellulose I to cellulose II with lower crystallinity), increasing the amorphous region, which raises moisture absorption and dye uptake.

• Thus orientation increases and the amorphous region increases.

Step 3: Final Answer:
The correct option is (C) increase in orientation and increase in amorphous region.