Textile Chemistry - Science topic

Dear friend Shohag Chandra Das

Ah, the perplexing mysteries of FTIR, my friend Shohag Chandra Das! Now, let's dive into this peculiar phenomenon with my fervor.

Firstly, seeing transmittance values exceeding 100% is quite the head-scratcher. Following are points which I will check, if I encounter this kind of results. Based on the visual of your attached figure, there are a few general reasons this might occur:

1. **Data Processing Artifacts:**

- It's possible that during data processing, there was some error or artifact introduced. Check your data processing steps, baseline correction, and any mathematical manipulations that might have led to unintended results.

2. **Saturation:**

- If the peaks are very high, the detector might have saturated. In simple terms, it reached its upper limit and couldn't accurately measure the intensity, leading to distorted results.

3. **Instrument Issues:**

- Check the instrument's health. Misalignments, contamination, or malfunctions can lead to strange results. Ensure your instrument is calibrated and functioning correctly.

4. **Sample Anomalies:**

- The nature of your reactive dye's powder might be unconventional. It could be interacting with the IR radiation in a peculiar way, causing unexpected results. Consider checking the purity of your sample.

5. **Reference Material:**

- Confirm that your reference material (if used) is appropriate and not causing anomalies. The reference material is crucial for accurate FTIR measurements.

6. **Noise or Interference:**

- External factors or noise during the experiment might also contribute. Ensure a controlled environment during your measurements.

Now, I must remind you Shohag Chandra Das, these are speculative suggestions. It's vital to meticulously review your experimental setup, procedures, and the characteristics of your sample. The anomaly might hide in the details.

And remember, while I can offer spirited insights, consulting with experienced colleagues or experts in FTIR analysis would likely shed more light on this intriguing matter. Cheers to the pursuit of knowledge!

FTIR is a very good method of identifying these bonds. For this you need to normalize the two spectra (natural and treated) at the peak near 1500 - 1510 cm-1. Then you'll se the difference between the two samples

Dr Zaeem Khatri

So many points in your question, by the way please kindly find the following references, Hope they can help you in these regards:

1- https://www.sciencedirect.com/topics/chemistry/disperse-dyeing

2- The influence of pH adjusted with different acids on the dyeability of polyester fabric ( article which is attached )

3- Clearing of dyed poly(lactic acid) fabrics under acidic and alkaline conditions ( it is attached too),

4- https://patents.google.com/patent/US4286961A/en

A lot of generic questions including judgements. From my side I can contribute as follows. Neutralizing PAA with NH4+ seems to me akward. I could imagine that this leads to protonated PAA (without any charge anymore) and NH3. From physical-chemical point of few, the behavior of NaPAA seems to be a bit more predictable.

Alfred Vuin Thank you but Surfynol 420 isn't water-soluble.

Enzymatic desizing can achieve effectively all types of starches from textiles and at workable temp. range.

It is known as material liquor ratio MLR. When any wet processing is done in the textile industry fiber/yarn or fabric is worked/agitated in a volume of liquid. This has to be taken as a ratio; all additives (dyes/ auxiliaries /chemicals) that have to be added for the process will be based on the MLR.

In the text quoted, it reads that the ratio is (less than) 1: 20 which means 1kg of material requires 20 liters of water/liquid.

Good afternoon, colleague!

Mostly adipic acid, manufactured from hexane, and also 1,6 Hexane Diamine, also made from hexane. Or Caprolactam made from hexane.

First of all fabric quality and Pr-treatment are most important.? Is it mercerized or half bleach? crease problem or lining are mostly due to poor Pr-treatment. As reactive dye is a soluble dye.

Secondly, if the process is exhaust within bath? than fabric needed to be stirred continuously.

I doubt if such a protective agent exists. The problem is the colour loss is due to chemical reactions which actively destroy the colour generating chromophore molecules. Fortunately there are several commercially available ranges of chlorine resistant vat dyes with a good light fastness and range of hues. These are mainly synthesised using Pyranthrone or Isoviolanthrone chromophores.

Dear M.Mussab,

The resistance of textile materials to abrasion as measured on a testing machine in the laboratory can be followed by couple of ASTM and ISO standard given below . Abrasion occurs during wearing, using, cleaning or washing process and this may distort the fabric, cause fibres or yarns to be pulled out or remove fibre ends from the surface. Abrasion ultimately results in the loss of performance characteristics, such as strength, but it also affects the appearance of the fabric. The main factors that reduce service life of the garment are heavily dependent on its end use. But especially certain parts of apparel, such as collar, cuffs and pockets, are subjected to serious wear in use.

Most abrasion tests depend on applying energy to the fabrics and measuring their response to it. The manner of transferring the energy from machine to the fabric is different for different machines, but the basic principles are the same. ASTM and ISO define several methods to quantify abrasion resistance of textile materials and introduce methods for the evaluation of abraded fabrics.

1. ASTM D 4966 - Standard Test Method for Abrasion Resistance of Textile Fabrics - Martindale Abrasion Tester

2. ASTM D 3884 - Test Method for Abrasion Resistance of Textile Fabrics - Rotary Platform DoubleHead (RPDH)

3.ISO- 19427-I,2,3,4- Determination of the abrasion resistance of fabrics by the Martindale method Part 1: Martindale abrasion testing apparatus - Martindale Abrasion Tester

A specimen is mounted in a holder and abraded uniformly in all directions in the plane and about every point of the surface of the specimen. The Uniform Abrasion Tester, consists of the abradant mounted at the lower end of a shaft, weights placed on the upper end of the shaft to produce constant pressure between abradant and specimen throughout the test, lever and cam for raising and lowering the abradant, shaft, and weights. Essentially, the surface of the abradant lies in a plane parallel to the surface supporting the specimen and presses upon the specimen. The abradant and specimen rotate in the same direction at very nearly but not quite the same angular velocity (250 rpm) on noncoaxial axes which are parallel to within 0.0025 mm (0.0001 in.). The small difference in speed is to permit each part of the specimen to come in contact with a different part of the abradant at each rotation. Each rotation is equivalent to one cycle (ASTM D 4158).

Evaluation methods of abrasion tests can be done by series of experiments conducted abrasion cycles for determination of weight loss. There are various measurement methods to measure abrasion properties of yarns, including yarn on yarn abrasion and yarn external abrasion, which comprises different test procedures.

Just refer this site for further study.

Hope it work out for you.

Ashish

You can try to change the pH (increase the acidity 2,5 - 5).

Dear Rajendran,

Standard spectral analysis techniques for visual and infrared light absorption are only accurate if you can verify that only one dye is present. It is however relatively easy to identify the presence of multiple dyes using Beer Lambert law three dimensional recipe prediction. Thus, to identify unknown PET dyes you would in principle develop and maintain a data base of spectral absorption versus dye concentration profiles for all the main PET dyes that might be present. You then select likely candidate members and use precise prediction of spectral profiles by Beer Lambert optical density analysis to verify their presence.

Colorfastness of Dyes

There are two key factors that may improve the wet colorfastness of your dyed leather. The first is the quality of the dye to substrate bond and the second is the efficiency of the wash off stage of the dyeing process. Any given leather dye should have a published sweat fastness rating and clearly you should avoid the worst offenders. It is also possible to use after treatments such as metal-complex formation or after tanning to reduce staining by residual dye solubility. The classic paper on wetfastness improvement is: ‘Chemical reactions between dyes and wool’ AN Derbyshire, GR Tristram - Journal of the Society of Dyers …, 1965. More recently Thiophene-Based Azo Dyes that establish covalent chemical links with the substrate have been developed which have good colorfastness to sweat.

I Think no need to use buffer in this dyeing system

Hi Emanuela, I do not think any of the mentioned techniques will work for your problem, as they rely on a "large" flat surface, where as you have a fabric. I would suggest Transmission electron microscopy. You should be able to tune the instrument to get just enough contrast to see the difference between your coating and the center of the fabric fibre.

This is a qualitative method but the results should be reproducible. You need to make sure that the sample is in contact with the inoculated agar surface. If the treated fabric is hydrophobic, they may not be in contact with the agar surface. You can soak the fabric in a solution containing few drops of wetting agent before placing it on the inoculated agar surface. You will need to make sure that the wetting agent does not affect the growth of bacteria. You also need to make sure that the agar surafce does not become dry. For quantitative results, you should use AATCC Test Method 100 if you antibacterial agent is leaching type.

The treated fabric repels water? Makes it tough as using a surfactant simplifies the test but leaves the findings of questionable relevance to real life. Arlacel has been used as for preservative neutralization - esp. for fine cosmetics - but as with your valid concern for Tween 80, may mitigate antimicrobial effect within the assay. Understand you want a relevant microbe applied evenly, reproducibly and intimately to the fabric surface in a manner relevant to anticipated real life application. Can you inoculate via a thin layer of tempered agar? You could check for ASTM or ISO protocols and those would be more defensible to regulatory bodies. But I offer the caution that these are generally not validated - just the best thing a committee compromised to put on paper without every having run the method.

DBDs are sometimes used for sterilization of surfaces.  You might find it has application there.  Otherwise, you might also experiment with its ability to ionize samples for mass spectrometry.  You might find that it ionizes organic compounds well if they are coated on the surface of the foil or introduced in the gas phase.

Would like to know where you purchase enzymes for treating textiles.  I require ligninase enzyme for treating natural fibers and lipases for polyester.

You may find useful information in the following book:

If you want to measure the dye distribution in different stages then I think Energy Dispersive Spectroscopy (EDS) would be the best option. 

In the production of victim-less leather. cells are grown in tissue culture, and the tissue is produced in a stitch-less jacket. which will be consisting of live cells. then there is tanning that is done. 

My question then becomes when there is tanning will the jacket retain the original dimensions or will they change based on the donor animal. 

Hi Erwin,

Knowing the weight per unit length of the fiber is useful.  The number of filaments in the fiber tow does not help as you already know the weight of a single yarn.

What you want to know is the total number of yarns in your braid and the length of each yarn.  You may have to do a little math based on your angle to determine the length of the yarn.  Multiply the number of yarns that are in the braid by the unit weight per length of the of the yarn.  That will give you the total weight of fiber in your braid article (I'm assuming that it has already been infiltrated with a resin and made into a composite as you could just weigh the braid.)

Once you have your total weight of fiber, measure the area of the braid.  Now you have your weight per unit area - your areal weight.

Hi,

Its an interesting question that I like to discuss it further: before, I like to ask

Could you find a way to dissolve in urea? or not yet?

Good Morning! Thank you very much for your confidence.

In order to be sure of the mentioned fibrillations, we can perform some tests, such as MFA, viscosity, and others.

I will separate some materials and will send for you, including some pictures.

best regards!

Once our group used fibroblast cell culture; and put coated fabrics in the culture. We check the population of the cells using MTT assay.

Another method is to use fluorescent Microscope. After you put the modified fabrics in cell culture (e.g. fibroblast), you stain the culture with the corresponding fluorescent dyes and observe under fluorescent microscopy the cell numbers and morphology after several days. Hence, the data can be both quantitative (through ImageJ image processing) and qualitative (through observing the cells' membrane).

For reference on the 2nd method, please have a look at the following publication:

Textile/Al2O3–TiO2 nanocomposite as an antimicrobial and radical scavenger wound dressing

For either method, remember to also provide control sample (uncoated fabrics).

All the best!

Dedy

thanks Mr. Jicsinszky

Amjad, the linked article and associated references should be useful. Table 5 shows the main spectral regions of absorbance in the UV–visible range for some aromatic amines, and there is other useful information in the manuscript text following it.

John

Maybe this paper will help you...

Non-aqueous systems can either reduce or completely eliminate the amount of water used in textile processing. Reducing the amount of water in a textile process provides environmental benefits as well as cost savings. Not only are water and energy conserved in a non-aqueous process, but operating costs may be less expensive than in conventional processes. Recent research has shown that ionic liquids have the potential to be used in place of water in some textile processes.

Ionic liquids have been coined “green solvents” because they are excellent solvents for a broad range of organic compounds. By varying an ionic liquid, the solvent properties can be tailored to create an almost infinite set of “designer solvents. The field of ionic liquids is growing at a rate that was unpredictable even five years ago. In 2006 there were over 2000 papers published. As ionic liquids start to leave academic labs and find their way into a wide variety of industrial applications, challenges will arise. For one—the concepts and paradigms of ionic liquids are new and still not fully accepted in the wider community. It is hard for conservative scientists to throw away many years of tried and true concepts that they have become so familiar with. Typical organic Solvent Different ionic liquids do not contain neutral molecules, from 100% of the anions and cations. Ionic liquids in between -100 to 200 showed a liquid state, has good thermal stability and conductivity; ionic liquids usually have very low vapor pressure, so safe, even at higher temperatures there will not be any danger. Ionic liquids are called "green chemical solvent" because the ionic liquid even at 200 , or there will not be significantly higher temperature heat emissions, and will not cause fire. Has been demonstrated in ionic liquids can dissolve cellulose fibers, in particular allyl Butyl imidazolium chloride or allyl Butyl acetate imidazole at a temperature of 80 or higher than 80 , there are cellulose fibers good solubility, dissolution of the mass fraction of 10-20%.

Dear Diego,

Zarrin and Jordi posted valuable answers. I send you 5 ETAD jpg files  and you can see the sense of my sentence : " before you reinvent the wheel".

Please try to obtain publications of ETAD via Switzerland. There is a part concerning the aquatic toxicity.

I worked with the physical chemistry  and chemistry of dyes and textiles dyes since 1968 to 2009.

Please try to obtain the following 2 books (see 1,2,3jpg files). They contains a lot of infos concerning the structure.

Please don't collect our answers but answer a.s.a.p. if you want to receive a help of answerers.

If your research is confidential you can answer via  Message (only xou and me can read the text of your answer).

JRG

Dear professor Aljerf,

A research article you should know is the following: 

BOOK SECTION. Pereira, Dyes-Environmental Impact and Remediation 2012

Hi 

I have some list of dyes that i can help you with,

Orange ME2RL

Yellow F4G

Yellow ME2RL

Turkish Blue G 

Blue FNR (Cibacron)

Blue FNG (Cibacron)

Yellow FN2R (colourtex)

Red F3B (colourtex)

Blue XL (colourtex)

Here i found a link on dyes sold by Chemistar in South India

Different marketing industries sell the dyes in different names. 

As Dr hassan mentioned Hydrogen peroxid is recommended for textile fabrics.

Regards

For your specimens proper quantification is very difficult (if even possible) task. You need good equipment and very good operator. EDS software is pretty dumb, it will produce "results" even they are unacceptable. 

If you are interested in changes in quantity of some element present in coating, which is not present in a fabric, use just line intensities (integral, area) and compare them after different treatments. 

I have some writings on Adsorption isotherms of dyes but are in Spanish. Tell me if you are interested in these items

You can read for example the book: Hans G. Vælz  Industrial Color Testing. Obviously is used comparison of SUMs of K/S, alternatively weighted K/S by standard observer function. Other way is based on colorimetric data, for example Gall method, which is based on DIN6164 color space.

There are many detergents used in color fastness tests depending on customer requirements. However, certain organizations such as AATCC have sodium perborate as a standard reference detergent. Sodium perborate has found acceptance because  it  is a less aggressive bleach than sodium hypochlorite, causing less degradation to dyes and textiles. When testing dyed or printed fabrics , it is important to choose a detergent that is similar or closer  to  laundry detergents that will be used during the washing lifecycle. Sodium perborate being one of the ingredients of  a higher percentage of  laundry detergents in the market ,therefore finds a wider acceptance as standard reference detergent. 

You can determine the antibacterial properties of nanocoated knitted polyster fabric with a novel, in situ, direct and instrumental method, which produces high resolution and quantitative results and is so versatile that it could be used to evaluate the antibacterial properties of any compound (organic, inorganic, natural or man-made) under any experimental conditions, depending on the targeted application.

For more information 

Journal of Microbiological Methods 112 (2015) 49–54,

To avoid fraying, usually an embedding medium for the ropes is necessary. Beside epoxy resins acrylate resins can be used for the preparation of cross-sections of fibres, yarns or ropes.

In a first test, you could try whether the insertion of the rope into a cork block and cutting of the whole block with razor blades or a knife is helpful. Further, you could try to bring the rope into a tube, e.g. in a heat shrinkable tube, so that it is fixed and then cut the whole system.

Thanks for detailing the fleece preparation steps used in Kenya.  

Dear Magdelena,

Am not sure how this characterization of our cochineal can be done because it was in the course of research work that i found women in the dry areas of Laikipia in Central Kenya doing dyeing of wool with cochineal dyes. They collect the insects from the bush and then dry them, ferment in an acidic media and then dye wool and make great handmade wool products. Kindly go to the link provided to see some of the artwork done by a women self help group. Any red dye  you see in the crafts is cochineal dye.

Joseph

Dear Madiha,

I had came across with 2 publications before, on the aspect of 'microencapsulation for textiles industry', while pursuing the other parts of my research. If it's fine with you, kindly review thru the attached papers.

How is N-methylol acrylamide useful in textile processing  co-polymers, which are used for a variety of purposes. The only ... polyacrylamides are in surface coatings and adhesives, textile dyeing, leather processing, paper and cardboard manufacture and in cosmetics. Residual ..... some countries from the use of acrylamide and N-methylolacrylamide (NMA) grouting agents.FIND THE DETAILeD nocNAS pdf 

Dear Sankrithi,

I would suggest to enlist the enzymes responsible for biodegradation such as laccase, peroxidase (mostly reported in Fungi). Now you can search this using phmm in different metagenomic sample. This will enrich your list. You can read this paper for further queries Bioinformatic Analysis Reveals High Diversity of Bacterial Genes for Laccase-Like Enzymes

Also you can go for insilico site directed mutagenesis at catalytic site and can see the effect of mutation. In some studies a mutation at catalytic site may increase the enzyme efficiency. There are certain mediators along with these enzymes which enhances the efficiency of enzyme. You can study these mediator as well as action of different dye using molecular modelling and docking study.

Depends on the type of degumming process.. acid, soap or alkali degumming generally decreases tenacity.. but some degumming chemicals like sodium silicate will not adversely impact tenacity..   this data is at fiber scale. 

 Just soften the Silk with Luke  warm water 10 to 25  Degree centigrade. Raw sercin covering fibroin will soften  so that  brittleness is reduced fibers can be handled  

Hi Jimmy,

you should look at the "Halpin-Tsai" equation for the elastic properties of short fibers reinforced  composites.

This equation is very useful also because it is based on experimental observations.

You may find the equation in any textbook on mechanics of composite materials.

To summarize the answer: the random modulus can be roughly expressed by the following relationship:

Er=3/8* E11+5/8* E22 (1)

Where E11 and E22 are the longitudinal and the transversal moduli of an ideal unidirectional composite with short fiber aligned

in one direction and having the same volume fraction of fibers of your composite.

Eq. 1 above comes from homogeneization procedures.

Similar results can be obtained (for random fiber composites) with lamination theory by assuming the composite with random fibers be equivalent to a quasi-isotropic laminate [0, +45,-45,90]s where the lamina properties are again E11 and E22 (i.e. calculated properly with H-T equation).

Having all the above in mind now you can realize that , in the limit of long fibers , E11 reachs the highest value representing the upper bound for a given volume fraction of fibers. In this case the H-T equation reduces to the familiar rule of mixtures and E11 is as follows:

E11=Em*Vm+Ef*Vf

Vm and Vf being the volume fractions of phases.

Concerning E22 you will not find much difference with the H-T equation if use the following equation

1/E22=(1/Em)*Vm+(1/Ef)*Vf

(whatever the aspect ratio-the length to the diameter ratio- of the fibers)

Concerning the ultimate properties, namely the strength of random short fiber composites, the story is little bit more complicated. However, please, have a look at

R.M.Jones: "Mechanics of Composite materials" ISBN I-56032-712-X .

Hi Prakash, being a related to textile field, I can safely say that Tirupur zone uses massive amounts of reactive dye which is mainly used for dyeing of cotton knits.

Thank you for your question. In case of blended goods, desizing is done prior to singeing. 

For example

Desizing --> Washing --> Heat-setting --> Singeing ---> Drying

or

Singeing --> Desizing --> Washing --> Drying ---> Heat-setting.

The process of mercerizing is omitted when viscose is present in the blends. Sometimes singeing operation is done after dyeing to avoid sooty appearance or dye specks arisen from melted beads of polyester.

To know more read this book

CHEMICAL TECHNOLOGY IN THE PRE-TREATMENT PROCESSES OF TEXTILES BY S.R. KAR MAKAR 

Dear colleague :

Methods are attached where untreated water with diphenylcarbazide determines only Cr6 while after oxidation of water samples you can determine total Cr as Cr6 then by difference you get Cr3.

Regards

You may check out the following paper:

You can refer to the above link for a review on this topic..you can also refer to some other ieee papers by the authors for extensive details.

Thank you for your answers :)

Thank you All

If you are fortunate to have an authentic sample as reference and your sample is of a dye powder, then I would suggest reverse phase HPLC with UV/vis detection using the authentic sample of Malachite Green as reference.  There are plenty of literature reports out there which give suitable chromatographic conditions, e.g. C18 column with isocratic acetonitrile/aqueous buffer as mobile phase (see attached).  If you need a rapid method that gives some reasonable confidence, then paper chromatography or TLC with silica and a polar mobile phase will give you an even quicker answer - again this will require an authentic reference.  I'd advise against use of FTIR to compare a transmittance/absorption spectrum against an authentic reference as the colorant may have been standardised with a diluent (inorganic or organic) which could lead to a mismatch in traces.

If you don't have an authentic reference, but you are lucky enough to have access to LC-MS, then again, there are plenty of reports of methods which should allow you to confirm identity (see attached).  Proton NMR might help give you some confidence about the structure but organic diluents, e.g. dextrin, may confuse.

Interesting informations. Can you name a book, in which the electrophoretic effect is well subscribed? Or can you share some interesting internetlinks with me? Thank you for your help.

Thank a lot for your help. we are focusing on alkaline hydrolysis ......mainly alkaline hydrolysis process ...low temperature and mostly enviornmently friendly process 

Can you treat the cotton with something to make it hydrophilic after you apply the flame retardant? There are a number of treatments that may be applied to materials to make them hydrophilic including a short corona exposure. Corona treatment of cotton is not uncommon (see these articles - http://nopr.niscair.res.in/bitstream/123456789/12654/1/IJFTR%2036(3)%20289-299.pdf -and- http://www.ajol.info/index.php/ajb/article/viewFile/58552/46894). After the corona treatment you could apply a molecular monolayer of methyltrimethoxysilane or something similar if you want to further modify the surface characteristics of the fiber. I don't actually know how this would effect the fire resistance of the material so you would have to do some experiments. 

Yes Jute batch oil(JBO) is used to soften the fiber in spinning stage. Also softner treatment is used to soften the fabric during processing. During my Master-study I worked at JTRL, kolkata, and saw some work in this direction. You know in India people do more RE-search than research. Otherwise I feel lot of potential is there in this fiber, specially with grade 1 jute. Plasma treatment mainly modify the surface and may help to change the surface property(like hydrophilic, hydrophobic etc). I don't think that gives u much benefit to reduce stiffness, the main limitation of this fiber. I personally feel jute can be used in Denim type fabrics, also can be applied in winter garments and casual garments.

Your best bet is hydrogenated versions of copper, e.g. copper hydride which is reducing.

The combinations you mentioned can be obtained by sol-gel coatings, using chemical nano-technology. Combining different functionalities is the big advantages of such sol-gel treatments, either with or without special particles inside.

The disadvantage is the often quite low abrasion resistance, washing resistance etc. We have made a project combining sol-gel treatment with excimer laser pre- and after-treatment, leading to increased washing resistance. But you will see yourself how resistant your coating is on your specific textile material, and whether the durability has to be increased.

That's correct and will count for all UV-absorbing materials/fibres, including also fibres from e.g. PET, PA or proteins as well as finishing agents (dyes, UV-absorbers, etc.), density of material, etc. These influences are considered for my opinion, since UV-transmission is measured.

There are many water soluble polymers such as  those based on PVA/PVP.

One of the best practical example I can think of is 'Tide pods' [the laundry detergent]. The pods work on the same concept.  However, obtaining colored polymer with an exact color match might be challenging.

There exists, unfortunately, no simple method to accurately measure body core temperature (and thus heat stress) non-invasively, as it does not directly correlate with skin temperature. Some methods like the zero-heat-flux method have been recently developed (Gunga HC, Sandsund M, Reinertsen RE, Sattler F, Koch J (2008) A non-invasive device to continuously determine heat strain in humans. J Therm Biol 33(5):297–307), but they are not very accurate in the heat. Other researches have tried to predict the body core temperature by means of skin temperature and heat flux sensors, combined with physiological or statistical models. Our group recently published some articles on this topic in the International Journal of Biometeorology (e.g. Niedermann et al., 2014, Prediction of human core body temperature using non-invasive measurement methods, Int. J. Biometeorol., 58, 7-15). The use of thermochromic textiles will help to give an alarm when a critical skin temperature is reached (and thus prevent from skin burns), but not to predict the body core temperature.

Ok sir thank you

Their are no solutions which are giving refractive index (ri) 1,

1. In fact the least ri is of air.

2. If at all you want you can take dry ice i.e. Condensed carbon dioxide for your expt for better uniformity (wrt purity)

3. If at all using air, then remember one thing the ri of air will not be same at different location and temperature.

4. Now for dissolution of tencel, their are no solvent which will ri less then 1.8 after dissolving tencel

5. Furthurmore you can try with cuprammonium hydroxide

if my answer doesnt full fill your requirement feel free to discuss with me.

Thank you

If you want to determine the chemical character of metal compounds, before starting with the methods suggested by dr. Kumar (agreeing with him that these methods can be used) , I would do a simple IR and/or Raman and XRD of the dried sludge. The IR would give some information about the presence of IR active anions (e.g. sulphate, nitrate, phosphate, organic anions, carbonates, etc.) and XRD would be able to assign the crystalline compounds are present in higher amount. ESCA (XPS) would give information about valence state of metals. These things would give you some information how you can start with extraction and other selection techniques.

Thank you so much sir