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The physical definition of plasma is an ionized gas with an essentially equal density of positive and negative charges.Different reactive species in plasma chamber interact with the substrate surface cleaning, modification or coating occurs dependent of the used parameter.Plasma process can be carried out in different manners,substrate can be treated directly in the plasma zone.substrate can be positioned outside the plasma; remote process. substrate can be achieved in the plasma followed by a subsequent grafting.substrate can be treated with a polymer solution or gas which will be fixed or polymerized by a subsequent plasma treatment.

Plasma Treatment In Textile DyeingDifferent reactive species in plasma chamber interact with the substrate surface cleaning, modification or coating occurs dependent of the used parameter. Furthermore the plasma process can be carried out in different manners. The substrate can be treated directly in the plasma zone. The substrate can be positioned outside the plasma; this process is called remote process. The substrate can be achieved in the plasma followed by a subsequent grafting. The substrate can be treated with a polymer solution or gas which will be fixed or polymerized by a subsequent plasma treatment.

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Plasma Treatment In Textile Dyeing

Plasma Treatment In Textile Dyeing

Dyeability of Cotton Substrate;

The effect of plasma treatment in air and oxygen appears to increase rate of dyeing direct dye uptake in the absence of electrolyte in the dye bath.

Oxygen treatment is more effective than air plasma treatment. It increases the rate and extent of dye uptake for the direct dye studied depends more on the oxygen component of the air than on the nitrogen component, which supports an oxidative mechanism of attack on the cotton.

Dyeability of Cotton Substrate:

It has been reported that plasma treatment on cotton in presence of air or argon gas increases its water absorbency. This report was concerned with the effect of air and oxygen plasma on the rate and extent of dye uptake of Chloramine Fast Red K on cotton print cloth. The effect of plasma treatment in two different gas atmospheres (air and oxygen) for different treatment times was studied by applying 2% of Chloramine Fast Red K.

The effect of plasma treatment in air and oxygen appears to increase both the rate of dyeing and the direct dye uptake in the absence of electrolyte in the dye bath. Oxygen treatment is more effective than air plasma treatment. This shows that the increase in the rate and extent of dye uptake for the direct dye studied depends more on the oxygen component of the air than on the nitrogen component, which supports an oxidative mechanism of attack on the cotton.

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The contributory factors leading to increase in dye uptake are as follows,change of the fabric surface area per unit volume due to the surface erosion.etching effect of the plasma effect on the fibred mages the fiber surface and also removes surface fiber impurities.chemical changes in the cotton fiber surface.possibility of the formation of free radicals on the cellulosic chains of cotton.

Thus the action of oxygen and air plasma treatments modifies the surface properties of cotton and leads to an increase in the rate and extent of uptake of direct dye.

The contributory factors leading to this increase in dye uptake :

The change of the fabric surface area per unit volume due to the surface erosion.The etching effect of the plasma effect on the fibred mages the fiber surface and also removes surface fiber impurities (e.g. cotton wax or any remaining warp size, etc.)The chemical changes in the cotton fiber surface (leading to carbonyl and carboxyl groups in the fiber.The possibility of the formation of free radicals on the cellulosic chains of cotton. Thus the action of oxygen and air plasma treatments modifies the surface properties of cotton and leads to an increase in the rate and extent of uptake of direct dye.

Dyeability of Synthetic Fibres:

In the synthetic fibres, plasma causes etching of the fibre and the introduction of polar groups. In this case, in situ polymerization of acrylic acid has been applied to polyester, polyamide and polypropylene fabrics in order to evaluate the improvement in dyeability of basic dyes. This procedure could later be extended by using different monomers to improve the affinity of these fibers for other types of dyes. The surface modification induced by grafting of polyacrylic acid has been investigated by scanning electron microscopy and Fourier transform spectroscopy.

Microdenier Polyester:

Plasma-induced surface modification of microdenier polyester produces cationic dyeable polyester fiber.SiCl4, silicone tetrachloride (ST) and radiofrequency generated (RF) generated plasma are used to create a polysiloxane type surface in polyester and provide sites for basic dyes. The researchers believe that the possibility of using basic dyes. On polyester could lead to a continuous flow system, low energy consumption, and more environmentally friendly consumption, low temperature dyeing technology on polyester substrates.

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DYEING IN SUPERCRITICAL CARBON DIOXIDE

This new process utilizes supercritical fluid carbon dioxide (CO2) for dyeing textile-materials.

It is a completely waterless dyeing process using only nominal amounts of CO2, nearly all of which is recycled.

DryDye fabrics dyed with this unique waterless process will have the same dye qualities and durability as current, conventionally-dyed fabrics.

ADVANTAGESNo waste water (problem in textile industry)No require additivesNo final dryingRecycling SolventColorantsEnvironmental friendlyDYEING IN SUPERCRITICAL CARBON DIOXIDE

NANOPIGMETSHybrid materials consisting of organic dyes and layered silicate nanoparticles Nanoclay: particle size < 20nmIonic-exchange reaction: Colorant + Nanoclay (H+)Nanoclays: Smectite groupMontmollonite: laminarSepiolite: acicular

In the past.nearly 25 % biodegraded in aerobic waste-water treatment plants. Remaining 75%was absorbed by the activated sludge and dumped in landfills along with the sludge.

A new generation of disperse dye from DyStarDIANIX ECO

Better dispersing action 90% biodegradable.can be applied in continuous & exhaust dyeing as well as textile printing. suited for customers with automated liquid dispensing systems.Dianix ECO A new generation of disperse dyes is now available from DyStar. Dianix ECO Liquid dyes incorporate a new dispersing agent system that has better dispersing action and is biodegradable.In the past.Only a small proportion of the dispersing agent (~25 %)was biodegraded in aerobic waste-water treatment plants. The bulk was absorbed by the activated sludge and dumped in landfills along with the sludge. A new dispersing agent has more than 90% biodegradability by the end of the test period. Due to the efficiency of the new product, only one tenth as much agent is needed in the first place. Combine less product with increased biodegradability and you meet all the requirements of the okotex 100 specification.Dianix ECO Liquids can be applied in continuous and exhaust dyeing as well as textile printing. They are particularly suited for customers with automated liquid dispensing systems.

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Sense the conditions in the environment and respond to those conditions Initially, smart colorants were developed for specialized applications but now have become available for application on textiles / Garments

Smart colorants can be classified into three categories

Photo chromic colorThermo chromic colorGlow in the dark color

Smart colorants for garmentsSmart colorants are those, sense conditions (such as differences in temperature or light) in their environment and respond to those conditions. Initially, smart colorants were developed for specialized applications but now have become available for application on textiles / Garments.Photo chromic color: Fabric color changes when exposed to sunlight or other source of UV radiation.Thermo chromic color: Fabric color changes with temperatureGlow in the dark color: Fabric color glows in dark.UsesOn garment to create novel products and promotional items like T-ShirtsOn fabric/garment to print company logo/brand name to prevent duplicationOn garment for party wear, night clubs etc.Thermometers and temperature indicators.Security printing.Food industry to indicate temperature of packaged food.

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FUTURE PERSPECTIVESPre-treated fibres:PET: with UV, N,N-dimethylacrylamideCO: DMDHEU, PUR, acetoneChanges in structure of colorants[6] Novel reactive disperse dyes has been synthesized. Control the solubility and dye process.Equations to predict the solubility.

Ultrasonic assisted dyeing?

1.1 What are Ultrasonic radiations?

There is a compression or rarefaction during each cycle of wave. When ultrasonic waves are absorbed in liquid system, the phenomenon of cavitations takes place, which is the alternate wave formation, oscillation and collapse of tiny bubbles or cavities. During the rarefaction of the portion of the wave cycle, dissolved gas molecules act as nuclei for the formation of cavities, which may expand relatively slowly up to a diameter as much as 0.1 cm. and then quickly collapse during the compression portion of the cycle.

DyeingThe use of ultrasound in the dyeing of textile can be explained as: when ultrasound waves are absorbed in the liquid system the phenomenon of cavitations takes place. Cavitations can liberate entrapped gases from liquid or porous materials like textiles, dye bath etc. The influence of ultrasound on dyeing is explained to have three-way effects:

(I) Dispersion: Breaking up of micelles and high molecular weight aggregates in to uniform dispersion in the dye bath.(ll) Degassing: Expulsion ( dissolved or entrapped gases or air molecules from fiber capillaries and interstices at the cross over points of fiber in to liquid and removed cavitations.(Ill) Diffusion: Accelerating the rate of diffusion of dye inside the fiber by piercing the insulating layer covering the fiber and accelerating the interaction between dye and fiber.

Effects I and II are promoted by the mechanical action of cavitations, while effect III is due to both the mechanical action and the heating of the fiber surface. In case of water soluble dyes, ultrasound constitutes mostly an effective means of mechanical agitation, whereas in case of pigments, which are not soluble in water, ultrasound provides means of pigment dispersion and penetration, which is not provided by the conventional method. The dyeing results are affected by the frequency of the ultrasound used. Irradiation at very low frequencies of the order of 50 or 100 cps produces no effects. Frequencies in the range between 22 and 175 KHz have been found to be most effective, the latter frequency being preferable for silk, wool and nylon

Ultrasonic offers many potential advantages in textile wet processing:

Energy savings by dyeing at lower temperatures and reduced processing timesEnvironmental improvements by reduced consumption of auxiliary chemicalsProcessing enhancement by allowing real-time control of color shadeSlower overall processing costs, thereby increasing industry competitiveness.

1.2 MicrowavesMicrowaves are electromagnetic waves whose frequency ranges from 1000MHz to10,00,000 MHz. Microwaves are so called since they are defined in terms of their wavelength in the sense that micro refers to tiny. In other words the wavelengths of microwaves are short at the above range of frequency, typically from few cms to few mm. The higher frequency edge of microwave borders on the infrared and visible light region of the spectrum.

Microwave dyeing:

Microwave dyeing takes into account only the dielectric and the thermal properties. The dielectric property refers to the intrinsic electrical properties that affect the dyeing by dipolar rotation of the dye and influences the microwave field upon the dipoles. The aqueous solution of dye has two components which are polar, in the high frequency microwave field oscillating at 2450MHz. It influences the vibrational energy in the water molecules and the dye molecules. The heating mechanism is through ionic conduction, which is a type of resistance heating. Depending on the acceleration of the ions through the dye solution, it results in collision of dye molecules with the molecules of the fiber. The mordant helps and affects the penetration of the dye and also the depth to which the penetration takes place in the fabric. This makes microwave superior to conventional dyeing techniques.

AirDye technology manages the application of color to textile without the use of water, providing a sustainable alternative to traditional cationic or vat dyeing processes. The process does not pollute water, greatly reduces energy use, lowers costs, and satisfies the strictest standards of global responsibility.

2. Air DyeingAirDye is a subsidiary AirDye Solutions As a world innovator, AirDye Solutions is passionate about creating new printing and dyeing technologies that improve quality, value, and accessibility while helping to sustain the planet.

Does not pollute water in the color application process. By using air instead of water to convey dye, no hazardous waste is emitted and no water is wasted.Greatly reduces energy requirements, thereby lowering costs and satisfying the strictest standards of global responsibility.Does not use boilers, screen printing machines, drying ovens, or cleaning and scouring chemicals, thereby eliminating major sources of pollution.Eliminates water in the color application step and simplifies the process, creating revolutionary possibilities of new industry and employment in unfarmable, arid regions of the world.

AirDye Technology

Gives consumers a way to choose style and sustainability at a realistic price at the point of purchase, thereby initiating world change.Is easy to specify, reduces cost, offers beauty and quality, and reduces environmental impact.Offers style without sacrifice. There is no dye-lot variation, no post-dye washing or treatments, and no minimum quantity.Offers exciting new options:Dye different colors on opposite sides of fabric.Dye fabric a solid color. Dye one side a solid color and the opposite side a print.Dye one side of fabric with a print and the opposite side with another print.Dye opposite sides of fabric with the same print.

How it Works?Conventional dyeing, such as vat dyeing or cationic dyeing, can produce visually acceptable results. On the down side, it uses polluting chemicals, a huge amount of precious water, and does not provide permanent coloration. Sublimation printing has been used to decorate synthetic textiles, but this process has limited application.

AirDye technology produces superior results compared to sublimation printing and conventional dyeing, but that is just the beginning of its advantages. AirDye technology also reduces detrimental impacts on the environment. And, because the dye is in the fiber rather than on the fiber, bleach and cleaning agents cant get to it; so colors look richer and last longer. The result is more beautiful colors and maximum color durability, with substantially less water and discharged chemicals.

For the mechanism of AirDyeing http://www.youtube.com/watch?v=6PUZRhskYN0