Tie Dye

Sahomy Rodriguez
February 16, 2014
H18

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

Pre-Lab Questions: 

1. Where did the art of dying fibers originate?

The art of dying fibers originated from India or China around 2500 B.C.

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

Natural dyes from plants were used such as berries, leaves, roots, the bark of a tree, and flowers.

     3.   What are the fibers of the socks made of?

The fibers of the shirt are made of cotton which is made up of cellulose molecules.

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

A co-valent (electron sharing) bond occurs between the fibers and the dye. The dye acts as a replacement for the chemicals lost (H) when pre soaking the fabric which allows the dye to be accepted into the thread.

Data:

1. Synopsis of what occurred before dying the shirt:

The socks was soaked in hot water for 5 minutes to increase the pH of the fabric and release the H atom of the cellulose molecule to prepare for the fabric to bond with the dye.

     2.  Process used to dying socks/tying method:

I folded then tied off every about an inch portion down of each sock to create stripes.

     3.  Describe pattern of socks after sitting for 24 hrs. :

All of the colors faded into each other but still have a slight white contrast between them from the rubber bands.

Post Lab Questions:

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

The bond between the dye and the cellulose has already been creating making the dye already apart of the thread. So the black dye bonds with the remaining white base of the shirt. 

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

The moistness allows the reaction of the dye with the fabric's fibers.

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

Cotton absorbs water easier than any other fabric as this dye is water soluble Fiber reactive dye bonds best with the cellulose fibers found in cotton.

    4.  What are some advantages of fiber reactive dyes?

Fiber reactive dyes are brighter, becomes part of the fiber creating a co-valent bond, and produces many colors.

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

The dye is absorbed by the shirt, that has an opposite ionic charge (dye+ O-).  The dye attracts/bonds to the cellulose from the cotton.