Question

\(TiO_{2}\) is used as an agent in manufacturing synthetic fibre for

• A. Stabilizing
• B. Lustering
• C. De-Lustering
• D. Antistatic

Hint:

Remember the applications of common additives used in synthetic fibre manufacture: \[ \begin{array}{|c|c|} \hline \textbf{Additive} & \textbf{Purpose} \hline TiO_{2} & \text{De-Lustering (Delustrant)} \hline Antistatic Agent & \text{Reduces Static Charge} \hline UV Stabilizer & \text{Improves Weather Resistance} \hline Pigments & \text{Colouring of Fibres} \hline \end{array} \] A simple memory trick is: \[ \boxed{ TiO_{2} \Longrightarrow \text{Scatters Light} \Longrightarrow \text{Less Shine} \Longrightarrow \text{De-Lustering} } \] This is one of the most frequently asked objective questions in Man-Made Fibre Technology and Textile Engineering.

Answer 1

The Correct Option is C

Concept: Synthetic fibres such as polyester, nylon, acrylic, and viscose possess a naturally smooth surface. As a result, they exhibit a high degree of lustre, which may not always be desirable for apparel applications. To reduce this excessive shine and produce a more natural appearance, certain additives are incorporated into the polymer before spinning. The most widely used additive for this purpose is Titanium Dioxide (\(TiO_{2}\)). Titanium dioxide is a white, chemically inert pigment that scatters incident light and thereby reduces the reflection from the fibre surface. Consequently, the fibre acquires a dull or semi-dull appearance.

Step 1: Understand the role of Titanium Dioxide in synthetic fibres.
During melt spinning or solution spinning, a small quantity of finely dispersed \[ TiO_{2} \] particles is mixed with the polymer melt or spinning solution. The dispersed particles scatter light in different directions, thereby decreasing the surface brilliance of the fibre. Thus, \[ \boxed{ TiO_{2}\ \text{acts as a delustrant (delustering agent).} } \]

Step 2: Benefits of adding \(TiO_{2}\).
Addition of titanium dioxide provides several advantages: \[ \begin{aligned} &\bullet\ \text{Reduces excessive lustre,} &\bullet\ \text{Produces a dull or semi-dull finish,} &\bullet\ \text{Improves resemblance to natural fibres,} &\bullet\ \text{Enhances aesthetic appearance,} &\bullet\ \text{Provides uniform optical properties.} \end{aligned} \] For this reason, \(TiO_{2}\) is commonly incorporated during the manufacture of polyester, nylon, and viscose fibres.

Step 3: Examine each option.
Option (A): Stabilizing Although stabilizers are added during polymer processing, titanium dioxide is not primarily used as a stabilizing agent. \[ \boxed{\text{Incorrect}} \] Option (B): Lustering Titanium dioxide does not increase lustre. Instead, it reduces the shine of the fibre. \[ \boxed{\text{Incorrect}} \] Option (C): De-Lustering Titanium dioxide is universally used as a delustrant to reduce the natural lustre of synthetic fibres. \[ \boxed{\text{Correct}} \] Option (D): Antistatic Antistatic finishes are obtained using different chemical agents and are unrelated to the function of titanium dioxide. \[ \boxed{\text{Incorrect}} \]

Step 4: Write the final answer.
Hence, \[ \boxed{ TiO_{2} \text{ is used as a de-lustering (delustring) agent in the manufacture of synthetic fibres.} } \] Therefore, \[ \boxed{\text{Option (C) is the correct answer.}} \]