FIBER DYEING PROCESS - Preparation 4

Cotton is usually bleached with (a)   agents such as hydrogen peroxide (H₂O₂).

During mercerization, the cotton fiber changes from a ________ shape to a ________ shape.

• flat; oval

• round; oval
• square; round
• triangular; cylindrical

Fluorescent whitening agents work by converting invisible ________ light into visible ________ light.

• visible, yellow

• visible, blue

• ultraviolet, blue
• ultraviolet, yellow

Which of the following is a reducing bleaching agent?

• Hydrogen peroxide

• Sodium hypochlorite

• Sodium sulphide

• Sodium chlorite

Which condition is essential to produce high luster in mercerization?

• High temperature

• Tension during rinsing

• Acidic solution

• Long reaction time

The main function of fluorescent whitening is to:

• Remove impurities

• Strengthen the fiber

• Convert UV light into visible blue light

• Reduce dye uptake

When evaluating whitening, instrumental assessment uses:

• Microscope

• Spectrophotometer

• Washing machine

• Light box only