Introduction

Welcome again to another experiment done by "The Master of Chemistry", John Blackson. Yes, this is one more assignment given by my teacher Ms. Janik; however do not get bored because this might just be the most fun project yet. This time the class was given the challenge of dying a plain white t- shirt. Not just dropping the the shirt in wet paint, but tying the shirt in such a way that the dyes will mix creating a nice pattern. Sounds fun just reading it doesn't it.

Objective

Use the process of dying fabrics to illustrate chemical reactions, equilibrium, chemical bonding, and pH.

Procedure

Step 1: With a permanent marker, write your name on the cloth you will be tie dying. There will be many other shirts in the lab during this activity; be sure yours is marked to avoid losing it.

Step 2: Soak your cloth in the hot water for about 5 minutes. Be sure you put it in the tub marked for your period.

Step 3: Put on a pair of gloves, remove your cloth from the soaking tub and wring out. Using the below diagrams, tie you cloth in one (or a combination of) the methods shown using string or rubber bands.

Step 4: Dye application. Apply the dye using the applicator bottles. Be aware that mixing will occur where the dyes come in contact with each other. Using complimentary colors (purple and yellows, blues and orange, or red and green) near each other usually produces a brownish black color. Also, the more dye you put on a given spot, the less white will remain on the final product.

Step 5: Place your dye-soaked item in a grocery or other plastic bag marked clearly with your name. No pooling of liquid should appear in the bag.

Step 6: After the cloth has soaked for at least 24 hours, open the bag, remove the item, and rinse it several times with warm water, before removing strings or rubber bands. Once it is rinsing clean, remove the ties and rinse several times again until it is rinsing clean. At this point, you can hang it to dry or place it in another bag to take home and wash.

*The first time you wash it, place it alone in the washing machine with just a small squirt of dish-washing liquid like Dawn or Joy. Do not use laundry detergent.

Pre-Lab Questions

1.) Where did the art of dying fibers originate?

The art of dyeing clothing fibers originated in India or China no later than 2500 B.C.

2.) Originally, what type of substances were used to dye?

Originally dyes came from parts of plants such as the bark, berries, flowers, leaves, and roots.

3.) What are the fibers of the shirt made of?

Cotton: Cellulose~ Oxygen and Hydrogen

4.) What chemical interaction is occurring when fibers are dyed?

Increasing the pH by soaking the fabric in calcium carbonate causes the release of Hydrogen atoms from the cellulose molecule. The removal of the Hydrogen atoms leaves the cellulose molecule with some atoms that do not have stable octets. As a result, the dye can bond to the cellulose molecule at the site of the removed Hydrogen atom.

Tie Dying Examples

Tie Dying History

The art of dyeing clothing fibers originated in India or China no later than 2500 B.C. Most natural dyes came from parts of plants such as the bark, berries, flowers, leaves, and roots.

In 1856, William Henry Perkin began the synthetic organic chemical industry by accidentally discovering the purple dye, mauveine,

when he tried to produce quinine from aniline.

About 100 years after Perkin’s first discovery, fiber-reactive dyes capable of forming covalent linkages with the fiber were discovered.

The Experiment

(THE DATA)

Let me start off by showing you my Blank t-shirt. Ms. Janik asked the class to bring in one for the experiment.

The first step was soaking the shirt in hot water. After five minutes, I rung out the shirt and got ready to tie it up. The class had many options on designs for our own shirts. Of course, I chose the best design of them all. The method of tying this shirt up was called "Double Spiral". Here are the steps of the "Double Spiral".

After tying the shirt up, I applied the dyes into the areas that I pleased. Unfortunately, there was a time limit and I came up short. I let the shirt dry for 48 hours. My creation would come out a little more white than I expected.

At least now I can use the excuse "I meant for the white to be there".

Post- Lab Questions

1.) If you dyed a rainbow spiral on a shirt and then soaked it in a black dye bath, the result would be a black shirt with a rainbow spiral pattern. Why doesn't the entire shirt dye black?

After a dye is applied, it is allowed to react in a desirable host environment for up to 24 hours. After this time, the bonding sites on the cellulose should be saturated with dye molecules. Excess dye molecules that have not bonded permanently are washed away using warm water rinse and a dye-carrying detergent. The remaining oxygen atoms would bond with the black dye making the shirt's design a black and rainbow mixture.

2. What is the purpose of soaking the shirts in the hot water for 5 minutes?

It increases the pH causing the release of Hydrogen atoms from the cellulose molecule. Now the Oxygen atoms are open to bond with the dye.

3. Why is 100% cotton the best type of cloth to use with fiber reactive dyes?

Cotton is made of long strands of cellulose molecules, all twisted together. Cotton is ideal for dying because the fibers are naturally hollow, and the dye molecules will form bonds on both the inside and outside of the fiber. If you put molecules of dye and cotton together, very little will happen until the atoms on the surfaces of the molecules are prepared for bonding.

4. What are some advantages of fiber reactive dyes?

Some dyes only stain the cloth, and wash out a little each time the cloth is laundered. High Quality dyes (fiber-active dyes) actually chemically (covalent) bond to the molecules of the fabric and can never be washed out. The dye molecules carry a “chromophore”, which absorb varying spectrums of light, allowing only certain spectrums to reflect.

5. Explain how ionic bonding is used to dye the shirts in this lab.

The fabric of the shirt is made of long twisted strands of cellulose molecules. Connected to these strands are the ions oxygen and hydrogen. A base takes the positive hydrogen ions away from the shirt when hot water is applied. This leaves the negative oxygen ions open to bond with the dye. The dye is a salt that bonds with negative chloride ions. When the dye and bonds with the shirt, the dye loses the chloride ions. The dye performs an ionic bond with the oxygen ions.