Name: Toby
Message: Since you're a scientist (who worked on the Human Genome Project, I see!), you know about cellulose powders and related materials (carboxymethyl cellulose; powdered dextrans; etc.).  I am also a scientist.  

I want to dye cellulose (and related) powders.

I want to test the different REACTIVE chemistries (mono-, di- and tri-chlorotriazines; vinyl sulphones; an azo dye; formazan; etc.)

My BIGGEST problems are: 
1. I only need to test ONE dye of each chemistry type (color doesn't matter).
2. I need to make sense of the recipes and adapt them to cellulose powder (cf., finished textiles).

MSDS's for reactive dyes are of no use regarding the chemistry.  Your pages have been the MOST helpful in that regard: Procion = chlorotriazines; etc..

I look forward to your reply and any advice and specific recommendations you can provide.

Thank you very much.


What are you testing them for? 

You should probably try to get similar dyes, with as close to the same chromophore group as possible. Otherwise the comparison may not make as much sense. Some dyes in a given dye class are much more quick to react than others of the same dye type, for example.

It should be easy to adapt the recipes to powdered cellulose. For each of your dyes, you'll probably want to use the same specific OWG (on weight of goods), which is just the weight of the dye powder relative to the weight of the fiber, expressed as a percentage. The different classes of reactive dyes require different recipes, and I can help you with finding them if need be. Washing the cellulose to remove the unattached excess dye will not be so easy, however, and it's essential. Is it clumpy enough to use a strainer? If you have to use filter paper, the process of washing will be slower, but you really do not want to confuse the unattached loose dye with the dye that has reacted with your cellulose. (I always recommend rinsing out the auxiliary chemicals first in cool water, then washing repeatedly in very hot water to remove the excess dye.)

Not all of the dye classes that you mention make sense. "Azo" dyes include any dye with an azo group, -N=N-, including chlorotriazines (see http://www.pburch.net/dyeing/FAQ/structure.shtml) and most vinyl sulfones (near the bottom of http://www.pburch.net/dyeing/remazol.shtml), so it makes no sense to say that you want to test one azo dye and one of each of the other dye types. 

Similarly, "formazan" refers to the chromophore (color-producing) section of the dye molecule, not to the reactive portion, and thus could be represented among different reactive dye classes. Formazan dyes include the bifunctional dye Procion Fast Blue H-EXL (Dystar) and the aminofluorotriazine dye formerly sold as Cibacron Blue F-R (now owned by Huntsman Textile Effects and probably called Novacron, if they still make it).

You may want to read John Shore's book Cellulosics Dyeing. It's inexpensive, only £9 plus shipping, if you order it directly from the Society of Dyers and Colourists in the UK. (If you find a used copy in the US it will probably cost $100.) It does not mention dyeing cellulose powders.