Tie dye experiment

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

Pre-lab questions:

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

The art of dyeing fibers probably originated in India or China.

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

Originally dyes came from parts of plants like the bark, cranberries, red cabbage, and safflower.

3.) What are the fibers of the shirt made of? The fibers of the shirt are made out of cotton.

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

Cotton fibers absorb water easily and are hydrophilic and the chemical reaction occuring when fibers are dyed depends on if a fiber can carry an ionic charge and combine with the oppositely charged colored ions. In order to dye cellulose a reactive dye must combine with the hydroxyl groups in the fiber.

History of dyeing fabrics:

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.

Chemistry of dyeing fabrics:

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.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.This can be done by either increasing the temperature or the pH of the fiber and dye. In this lab, we will do the latter, increasing the pH by soaking the fabric in calcium carbonate, which causes the releases a H atom from the cellulose molecule. The removal of the H atom 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 H atom. After the 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.

Procedure:The point of tie dying is to prevent the dye from reaching the fabric evenly. Any place the dye can’t reach will stay white, or a lighter color. You can accomplish this by folding the fabric, tying it with string, using rubber bands

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 dishwashing liquid like Dawn or Joy. Do not use laundry detergent.**

Data:

1.) Write down a synopsis of what occurred before the dying of the shirt:

         Before the dying of the shirt the I folded my shirt into a knot and placed rubber bands around it so that I could differentiate which shirt belonged to me since some of my classmates were also putting their shirts into the bucket. The shirt was then placed in a bucket of hot water for about five minutes and then it was wrung out so that it would not leak water all over the classroom and then, I was able to take off the rubber bands and lay my shirt flat onto one of the tables and began twisting it in the middle to form my desired design and then put rubber bands around it to secure my design in place. After that, I was finally able to begin dyeing my shirt.

2.) Explain the process used to dye your shirt - pattern, tying method.
First, I pinched the shirt in the center and then began twisting it until the entire shirt was in the shape of a spiral. After that, I placed rubber bands around it to make sure it stayed in that shape securely. In the end it kind of reminded me of a whirl wind.

3.) After the shirt sat for 24 hours, describe the pattern of the shirt-picture if possible.
         The pattern of my shirt after twenty four hours was the two colors yellow and purple in the shape of a spiral around the shirt with specks of blue, red, and green splattered on it in random places.

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?

The entire shirt does not dye black because what was bonded beforehand can not be undone, therefore the rainbow dye is unaffected. The shirt appears with black dye because it must have bonded with the white spaces on the shirt that were yet to be bonded with because of the rubber bands that were placed on the shirt preventing those spaces from being dyed before.

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

The purpose of soaking the shirts in hot water for 5 minutes is to prepare the shirt for the bonding of dyes by increasing the temperature of the shirt and acting as a base for the dyeing process.

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

Cotton is ideal for dyeing because the fibers are naturally hollow, and the dye molecules will form bonds on both the inside and out of the fiber.

4.) What are some advantages of fiber reactive dyes?

Advantages of fiber reactive dyes are actually chemically (covalent) bonded to the molecules of the fabric and can never be washed out. 5.) Explain how ionic bonding is used to dye the shirts in this lab.

A base comes in and pulls the hydrogen off the cellulose. After that, your left with a potential bonding site. And the thread is left ready to accept the dye molecule.

sources:
http://www.ehow.com/list_7247662_flowers-used-dye.html

https://www.westminster.edu/acad/sim/documents/STie-dyechemistry_000.pdf