Question

Among the following circular cross section fibres, which absorbs more dyes in dyeing

• A. Star shaped
• B. Trilobal shaped
• C. High tenacity
• D. Pentalobal shaped

Hint:

• Fiber cross-sectional shape affects surface area. Profiled fibers (trilobal, pentalobal, star, etc.) have higher surface area per unit volume/mass than circular fibers of the same fineness.
• Higher surface area can lead to faster initial dyeing rates}.
• The optical properties (luster, perceived color depth) can also be affected by cross-sectional shape. Trilobal fibers are known for silk-like luster and can appear to have richer colors.
• Equilibrium dye uptake (total amount of dye absorbed) is more fundamentally determined by the fiber's chemical nature, internal morphology (amorphous vs. crystalline regions), and availability of dye sites.
• High tenacity fibers (highly drawn, more crystalline/oriented) generally have \textit{lower} dye uptake.
• If "absorbs more dyes" implies better dyeing performance including rate and appearance, trilobal is a known beneficial modification.

Answer 1

The Correct Option is B

In textile engineering and fibre science, the shape of the fiber cross-section significantly influences dye absorption. This is because the surface area exposed to the dye plays a crucial role in the fiber's ability to absorb colors. To determine which shapes absorb more dye, we should consider the following:

• Star shaped: Offers a high surface area due to its points and edges, potentially increasing dye absorption compared to circular fibers.
• Trilobal shaped: This shape resembles a three-lobed figure, like a triangle with rounded edges. The increased surface area compared to a circular cross-section enhances dye absorption.
• High tenacity: Refers to the fiber's strength and is not directly related to cross-sectional shape or dye absorption.
• Pentalobal shaped: Similar to the trilobal but with five lobes, which also increases dye absorption over circular fibers.

Among these, the trilobal shaped fiber is specifically engineered to increase the surface area while maintaining fiber strength, thus enhancing its capacity to absorb more dye. Therefore, the correct answer is the trilobal shaped fiber.