Acid vs. MX Reactive Dyes: Silk, Linen, & Cotton

Kristin A. Lord

Student Projects, Pigments/Dyes/Binders


The purpose of my final project is to compare how Acid Dyes and MX Reactives dyes react with different types of fabrics including silk, linen, and cotton. I plan to test both types of dyes on all three types of fabric and determine the differences in the fabric's reaction to the dye. I also will use the Colorimeter to measure the color content of each dyed fabric to determine possible differences in dye reactions that would affirm or negate visual hypotheses.

I went into this experiment with two hypotheses. My first hypothesis was that the acid dye would work better on the silk. I thought this would be true because of the information presented to our class by Carol LeBaron. She said that acid dyes were most widely used on silk. My second hypothesis was that the mx reactive dyes would work best on the cotton and linen. Carol had said this was the case because these dyes react quickly with cellulosics.


I am gong to provide a recap on the chemistry of dyeing fabrics. Dyes are defined as a colorant that does not require a binder to adhere to a substrate and are usually composed of different chemical groups responsiible for its respective properties. They dye reacts with the fiber by forming bonds with the fabric depending on the type of fabric involved. Silk, for example, is a polymer and forms multiple amide/peptide links. In my project I used acid dyes and mx reactive dyes. When the water evaporates out of the fabric, the dye is left in it as part of the fabric. The color of the dye depends on which colors of light the fabric reflects and absorbs. For example, if a fabric appears blue, it is absorbing red and green light. Acid dyes' properties include being reactive with protein and polyamide fibers, requiring heat for a reaction, requiring an acid be added to the bath, being long-lasting, and the dye solution should be exhausted. The properties of mx reactive dyes include reacting well wth cellulosics, not requiring heat, requiring a base to be added, only lasting up to two weeks, and they are not exhaustable.


Day 1: Thursday, April 17th 2003, 9:30-10:50am, 1-3:15pm

On day one I started work on my lab project by determining needed ingredients to dye the three types of fabrics with acid dyes. In the morning I mixed the materials for the linen in a room-temperature bath of water and left it to soak. In the afternoon, after consulting Dr. Bordley, I realized I had gone about the process incorrectly. The results of that dye soak were, nevertheles, interesting and will be included in my conclusions on my project. I resumed the project in the afternoon and used the combinations of materials in Data Entry 1.

I soaked each of the fabrics in water and Synthrapol for 30 minutes. I then mixed the ingredients into beakers and heated the fabrics for 30 minutes but, by mistake, they were never set to boil. I removed the fabrics from the beakers and put them in plastic bags to redye them later. I covered the beakers and contents with saran wraps to be used at a later date.

Day 2: Friday, April 18th 2003, 1:30-4pm

On day 2 I uncovered the beakers, inserted the fabrics, and set all three to boil. The silk was boiled for an hour at 85 degrees Celsius. It could not get as hot as the other fabrics because of its delicate nature. The linen and cotton were boiled for an hour at 100 degrees Celsius. After an hour the fabrics were allowed to cool before I rinsed them out with water and hung them to dry.

Acid dye baths on heaters.

Top thumbnail shows dyeing resulting from an error: using a room temperature bath.


Bottom thumbnail shows dyed materials and remains of baths at the end of day 2.

Acid dye results: linen, cotton, silk, top to bottom thumbnails.


Day 3: Tuesday, April 22nd 2003, 9:30-11:30am

On day 3 I determined the needed ingredients for dying the fabrics with MX Reactive dyes. I used the combinations of materials found in Data Entry 2.

I measured out theingredients into individual beakers and labeled them based on the fabric type they would be used for.

MX Reactive dye results:silk, linen, cotton, top to bottom.


Day 4: Friday, April 25th 2003, 1:30-4pm

On day 4 I mixed the materials for dyeing each type of fabric into a large beaker (except for the dye activator which would be added later). I set all three to boil for an hour. The silk was dyed at 85 degrees Celsius and the cotton and linen at 100 degrees Celsius. After an hour I allowed all three to cool, rinsed the fabrics in water, and hung them to dry.

Day 5: Monday, April 28th 2003, 10-10:15am

I used the Colorimeter to Measure the Lightness/Darkness and amounts of blue and red in all the fabrics. The values can be seen in Data Entry 3.

Observations and Data

Data Entry 1: (Day 1)

Linen (27.1 g):

Silk (41.5 g):

Cotton (44.06 g):

Data Entry 2: (Day 3)

Linen (27.1 g):

Silk (41.5 g):

Cotton (44.06 g):

Data Entry 3: (Day 5)

Fabrics with Acid Dyes

Fabrics with MX Reactive Dyes


My results were very interesting. I think visually the mx reactive dyes reacted better with the fabrics than the acid dyes, confirming my hypothese about its reaction with cotton and linen. The colors turned out much richer. My hypothesis about the silk, however, was also confirmed. The silk reacted no where as well with the mx reactive dyes and ended up looking almost tie-dyed. I am not sure exactly why that is. It must have had something to do with the way the silk was positioned in the beaker that resulted in uneven dyeing though this never happened with any of the other samples. It was also interesting that the linen soaked in the cool-water immersion did absorb some dye though not as evenly as the heated sample. This is most likely because lack of heat does not facilitate for good reactions between the fabric and dye solution.

The colorimeter results were also interesting and reflected the conclusions I had made visually. The measurements for the mx reactive dyes in comparison to the acid dyes were very different. The mx reactive dyes showed up with more positive values, making the fabrics brighter and richer in color. The silk sample, however, was the exception with two negative values.


Pro Chemical Website

Other References

I used materials from Carol LeBaron's lecture, Dr. Bordley's Dye Lab, and the Pro Chemical Website.


I would like to thank Jennifer Bachman for her extensive help in locating my materials and Emily Shade for helping me quickly reformat my whole webpage in the record time of 45 minutes . . . go us!!