Plasma treatments in dyeing

2.  Introduction about plasma
 Objective
 classification of plasma
 How LTPs is generated
 How does plasma work
 Working pressure of plasma
 Plasma on textile& its uses
 Application of plasma technology
 Advantages
 Dis advantages
 Refernces

3.  More than 99% matters of the universe are plasma.
 Plasma is the 4th state of matter.
 Plasma is an ionized form of gas and can be created by using
a controlled level of AC or DC power and can be ionized gas
medium.
 It is more or less an electrified gas with a chemically reactive
media that consists of a large number of different species
such as electrons, positive & negative ions, free radicals, gas
molecules in the ground or any higher state of any form of
excited species.

4.  Plasma is applied as a finishing agent for textile materials.
 With the help of plasma finishing, they are excellent for
imparting additional functionality like hydrophobic, oleo
phobic, antibacterial, desizing etc.
 It can change the surface characteristics of textile materials by
radical formation( attachment of functional group and
deposition/polymerization ) and etching of materials surface.
 Plasma finishing is a dry processing technique ( without water)
and provide a solution to reduced the chemical, water &
energy.
 Environment friendly process.

5. Plasma can be distinguished into two groups;
 High temperature or fusion plasmas
 Low temperature or gas discharge plasmas
now, low temperature plasma is further divided into two;
 Thermal plasma
 Cold plasma
 Only low temperature plasma (LTPs)are suitable for surface
modification of heat sensitive polymeric and textile materials.
 Low temperature plasma technology both glow discharge under
reduced pressure as well as barrier discharge under normal
pressure are well established in different industrial application.

6.  An LTPs can be generated by applying an electrical field over
two electrodes with a gas in between or by inducing
radiofrequency (RF) resonant current in a coil. This can be
carried out in a closed vessel under reduced-pressure or at
atmospheric-pressure. LTPs contain many reactive species
including fast-moving electrons, ions, free radicals, meta-
stables, and photons in the short-wave ultraviolet range. All of
these species can initiate physical and chemical reactions on
the surface of a substrate. Such changes are confined to a
depth of a few nanometers i.e. the plasma only affects the
outermost thin layer of the substrate.

7.  Firstly, gases are heated and charge to plasma state.
 Then the fabric is placed between two electrode.
 After this gases are directed on the sample piece in the form
of high velocity.

8.  There are two types of plasma pressure can be used for
application of textile.
 Vacuum pressure plasma :- plasma can not be generated into
a complex vacuum the name vacuum pressure is some what
misleading and only refers to the low working pressure (0-
0.0069 atm) of such system.
 Atmospheric pressure plasma:- Atmospheric pressure plasma
working at atmospheric pressure ( 1 atm).

9.  The plasma gas particles etch on the fabric surface in nano scale
so as to modify the functional properties of the fabric.
 Unlike conventional wet processing which penetrate deeply into
fibres, plasma only reacts with the fabric surface that will not
affect the internal structure of the fibres.
 It can modify the surface properties of textile materials.
 Textile manufacturers and end-users alike have been searching
for ways to improve the surface properties of natural and man-
made fibers. Specifically, there is a need to improve adhesion,
wet ability, printability and dye ability; as well as to reduce
material shrinkage. Methods of modifying fiber properties to
make polypropylene (PP) dye able, including the process of
copolymerization with polymers that can be dyed, have been
evaluated

10.  DESIZING
 WET ABILITY ENHANCEMENT
 WATER/SOIL REPELLANCY
 PRINT ABILITY
 DYE ABILITY
 SHRINK RESISTANCE
 ADHESION RESISTANCE
 STERILIZATION

11.  Plasma technology can be used to remove PVA sizing materials
from cotton fibres.
 In conventional desizing process we use chemical and hot
water to remove sizing materials.
 Desizing with plasma technology we can used either 02/He
plasma.
 Now, firstly the treatment breaks down the chains of PVA
making them smaller and more soluble . X ray photoelectron
microscopy results publish that plasma treatment introduces
oxygen and nitrogen groups on the surface of PVA which
owing to great polarity increase thee solubility of PVA.

12.  Plasma treatment of wool fibres has shown to reduce this
curling effect by etching off the exocuticle that contains the
disulphide linkages which increases the cross linkage and
contribute towards shrinkages.
 This procedure also enhances wet ability by etching off the
hydrophobic epicuticle and introducing surface polar groups.
This increase in surface area of the fibre.
 For this process we may use oxygen, nitrogen or mix of these
gases.

13.  Dye ability or printability of textiles can be markedly improved
by plasma treatments.
 This effect can be obtained on both synthetics and natural
fibres.
 Capillarity improvement, enhancement of surface area,
reduction of external crystalinity, creation of reactive sites on
the fires and many other action can contribute to the final
effect depending on the operative conditions.

14.  The graph shows that plasma treated wool can achieved 90%
exhaustion in 30 minutes as compared to 60 minutes for
untreated samples.
 When wool is dyed with reactive dyes maximum exhaustion is
achieved by A possible explanation to this behavior of reactive
dyes is due to increase in sulphonate groups on the fibre
surfaces.

15.  It increase abrasion resistance of cotton materials.
 It increases dyeing speed.
 It gives anti dirt properties.
 It increases hydrophilicity of fabrics.
 It increase the color & wash fastness.

16.  This treatment produce harmful gasses such as ozone and
nitrogen oxide during operation.
 High cost of plasma device.
 Less availability.
 Required skill operator.