2c. Explain why some of the fabrics get dyed (no mordants) very well while other
ID: 716691 • Letter: 2
Question
2c. Explain why some of the fabrics get dyed (no mordants) very well while others do not. Your discussion should be based on the chemical structures of the fibers and dye and should cite the specific types of non-covalent interactions that are relevant. Although you do not know the exact structure of the dye that came from your plant, you can speculate that it is polar because it is soluble in water, and that it probably has lots of oxygen atoms and possibly nitrogen atoms (H- bonding), and that it may be ionic.Explanation / Answer
Dyes are the coloured chemical compounds that get adsorbed over the fibre to make it coloured. The extent of adsorption depends upon the type of interactions occurs between the fibre and dye, if the interaction is strong (for example ionic bonding, hydrogen bonding, etc) then dye get adsorbed easily on the textile fibre. Whereas, if the fibre or dye does not have polar functional groups the interaction would be weak like dipole-diploe interaction and other vander wall interactions, since there interactions are weak in nature therefore the dye cannot be easily adsorbed over the fibre.
Now, in those cases where no strong interaction occurs and dye has very low affinity towards the fabric then we need mordants (generally metal salts like Al, Fe, Cr, etc.) which help the dye to get fix over the fabric by making a co-ordination complex (chelate). For acidic dyes we use basic mordants such as metal ions salts, i.e., in your case and for basic dye an acidic mordant like tannic acid is used.
In your case, check whether the dye you are using is acidic or basic, if acidic then FeSO4 is the correct mordant, if not then change the mordant.
Moreover, if your dye is soluble in water, then it should be polar or it should be forming hydrogen bonds with water and if not then it should be non-polar or less polar.
Once you find out that the dye is soluble in water then it can be easily adsorbed over those fibre which have polar functional groups such as (-OH, -NH2, -COOH, etc), First dye all those fabrics without mordant, fabric which adsorbs dyes easily without the help of mordant means they are undergoing strong adsorption and the interaction between those fibres and dyes should be ionic or hydrogen bonding.
The next step is to dye rest of the fibre with the help of mordant, this way you can get them coloured easily. Mordant first get adsorbed over the fibre then the functional group of dye would form strong coordination bond with that ions (Fe here).
Wool and silk on the other hand have -NH2 (amine group), thus undergoes strong polar interactions. If you use mordant then they would absorbed even fast due to ionic interactions.
Cellulose and its derivatives required mordant hence they are undergoes dipole-diople interaction or wanted wall interaction, once they are dyed with the help of mordant then the interaction is strong coordination bond
Dyes are the coloured chemical compounds that get adsorbed over the fibre to make it coloured. The extent of adsorption depends upon the type of interactions occurs between the fibre and dye, if the interaction is strong (for example ionic bonding, hydrogen bonding, etc) then dye get adsorbed easily on the textile fibre. Whereas, if the fibre or dye does not have polar functional groups the interaction would be weak like dipole-diploe interaction and other vander wall interactions, since there interactions are weak in nature therefore the dye cannot be easily adsorbed over the fibre.
Now, in those cases where no strong interaction occurs and dye has very low affinity towards the fabric then we need mordants (generally metal salts like Al, Fe, Cr, etc.) which help the dye to get fix over the fabric by making a co-ordination complex (chelate). For acidic dyes we use basic mordants such as metal ions salts, i.e., in your case and for basic dye an acidic mordant like tannic acid is used.
In your case, check whether the dye you are using is acidic or basic, if acidic then FeSO4 is the correct mordant, if not then change the mordant.
Moreover, if your dye is soluble in water, then it should be polar or it should be forming hydrogen bonds with water and if not then it should be non-polar or less polar.
Once you find out that the dye is soluble in water then it can be easily adsorbed over those fibre which have polar functional groups such as (-OH, -NH2, -COOH, etc), First dye all those fabrics without mordant, fabric which adsorbs dyes easily without the help of mordant means they are undergoing strong adsorption and the interaction between those fibres and dyes should be ionic or hydrogen bonding.
The next step is to dye rest of the fibre with the help of mordant, this way you can get them coloured easily. Mordant first get adsorbed over the fibre then the functional group of dye would form strong coordination bond with that ions (Fe here).
Wool and silk on the other hand have -NH2 (amine group), thus undergoes strong polar interactions. If you use mordant then they would absorbed even fast due to ionic interactions.
Cellulose and its derivatives required mordant hence they are undergoes dipole-diople interaction or wanted wall interaction, once they are dyed with the help of mordant then the interaction is strong coordination bond
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.