Key Concepts
Dyes, fabric

Introduction

Have you ever wondered about the materials that your clothes are made out of?  The clothes you wear are made of fibers that come from many different sources.  Some fabrics are made from natural fibers, and some from manufactured or totally synthetic fibers.  In this activity, you’ll explore how well different fiber types are dyed using fiber-reactive dye.  Aren’t you just dye-ing to find out which fabric works best?

This activity is not appropriate for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.

Background

From the shrouds of mummies in ancient Egypt, to the ball gowns of ladies in the Victorian era, to the tie-dyed shirts of modern hippies, dyed cloth has played an important role in human society.  Its production has also changed over time.  Early dyes were made using natural resources, like plants, berries, minerals, and seeds.  The cloths, just like the dyes, were made from a natural resource – natural fibers, like cotton, linen, wool, and silk.  Cotton and linen fibers are formed from cellulose, the main component of plant cell walls.  Wool and silk are animal-protein-based fibers.    

Materials

  • Three different types of white fabric samples: linen, cotton-polyester blend, and 100% polyester.  Purchase enough to make at least one 10 inch by 10 inch square of each type.  
  • Ruler
  • Scissors
  • Permanent marker
  • Newspaper or rags
  • Measuring cup.  It should not be used for cooking afterward.
  • Laundry detergent
  • Safety goggles
  • Rubber gloves
  • Clean glass jar, at least 10 oz.  It should not be used for food or beverage afterward.
  • Measuring teaspoon and tablespoon.  They should not be used for cooking afterward.
  • Fiber-reactive dye powder, such as Tulip Permanent Fabric Dye or Procion Pro MX Reactive Dye, often available at a craft and/or fabric store.  Use a bold color, like red, blue, or green. 
  • Salt
  • Water
  • Sealable plastic bag, 1 gallon size
  • Timer or clock
  • Soda ash or Arm & Hammer Super Washing Soda
  • Plastic container that can hold 4 cups comfortably.  It should not be used for food or beverage afterward.

Preparation

  1. Cut at least one 10 inch by 10 inch square out of the each fabric sample (linen, cotton-polyester, and 100% polyester).
  2. Use the permanent marker to label each square with its fabric type.  Because the permanent marker may leak through some types of fabric, if you are not working on a surface that can be stained, you should label the fabrics on top of newspaper or rags.
  3. Pre-wash the fabric squares by putting them in a normal clothes washing machine with ¼ cup laundry detergent.  Wash using hot water, if possible.  Allow the fabric squares to air dry.
  4. Before opening the dye powder packet, cover the area you will be working on with newspaper or rags so that you will not stain it.  You may want to work outside to avoid staining something.  Also put on clothes that you would not mind staining.
  5. Dyes often contain soda ash (sodium carbonate), which is caustic.  Wear goggles and gloves when mixing the dye solution, mixing the soda ash solution, and rinsing the fabric samples after dyeing.

Procedure

  1. Put on gloves and safety goggles.
  2. Put 2 teaspoons of powdered dye, 1 tablespoon of salt, and 1 cup of warm water into the glass jar.  Mix thoroughly.  How does the dye look?
  3. Wet the fabric squares and place them in the sealable plastic bag.  Carefully pour the dye solution into the bag and add ½ cup of water to the bag.  Seal the bag, trapping as little air as possible.  How does the fabric change when the dye is added?
  4. Let the bag sit for 20 minutes.  Every couple of minutes, gently squeeze the bag to coat all of the fabric samples.  
  5. While the fabric’s soaking, mix 1 tablespoon of soda ash (or Arm & Hammer Super Washing Soda) with 2 cups of warm water in the plastic container.  Break up any hard pieces that form.
  6. After the fabric’s done soaking, carefully open the plastic bag and add ½ cup of the soda ash solution.  Reseal the bag, trapping as little air as possible.
  7. Gently squeeze the bag to mix the soda ash, dye, and fabric.  Let the bag sit for 1 hour, gently squeezing every 10 minutes.
  8. Carefully dump the contents of the bag into a sink and rinse the fabric until the water runs clear.  
  9. Wash the fabric samples in the washing machine just as you did before.  Allow the samples to air dry.  When you are done handling and disposing of the soda ash solution, you can remove your goggles and gloves.
  10. Once they’re dry, how do the fabric samples look?  Did some types of fabric become dyed to a darker shade than others?  Did some types not absorb much dye at all?   

Extra: In this activity, you tested how well linen, cotton-polyester, and polyester samples were dyed using a fiber-reactive dye.  But there are many other types of fabric you could test dyeing, such as cotton, wool, rayon, silk, and nylon, and they may react differently.  How well do other types of fabric become dyed with a fiber-reactive dye?

Extra: Before synthetic dyes were created, humans used natural dyes.  Do some background research and pick one or more natural dyes to try in this activity.  You will probably want to use relatively safe dyes, like turmeric or berries.  Do some natural dyes work better than others?  Does it depend on the type of fabric used?

Extra: Some dyeing methods suggest pre-soaking the fabric in soda ash solution, and then adding dye (the reverse of what is done in this activity).  Does the order of these steps make a difference in the color of the dyed fabric?  

Observations and Results

Did the linen fabric become dyed the darkest shade?  Did the polyester fabric remain nearly white?  Did the cotton-polyester fabric become noticeably dyed, but not quite as dark as the linen fabric? 

Cotton and linen fibers are both natural fibers made from cellulose, a compound found in plant cell walls.  Fiber-reactive dyes form permanent covalent chemical bonds with cellulose, making this dyeing process a relatively permanent one.  Polyester, however, is a synthetic fiber that does not react with fiber-reactive dyes in this way and cannot be effectively dyed using them.  For polyester to be successfully dyed a different category of dyes must be used, specifically dispersion dyes, and a great deal of heat applied during the dyeing process.  In this activity, you probably saw that the polyester fabric was not effectively dyed, remaining nearly white, while the linen fabric was dyed the darkest shade, and the cotton-polyester fabric was not quite as dark as the linen fabric (depending on the percentage of cotton and polyester in the fabric).    

Cleanup

  1. You can safely pour the extra soda ash solution down the sink, flushing with water.  Do not use the measuring cup, measuring spoons, plastic container, or glass jar for cooking or food afterward.  Carefully rinse and then recycle the plastic sealable bag.  

More to Explore

Credits

Teisha Rowland, PhD, Science Buddies

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Key Concepts
Dyes, fabric
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