i hope it will help

1. Recent advances in
chemical processing of
synthetic fibres and yarns
Ksh Dolly
L-2021-CS-145-D

2. Chemical
processing
• Chemical processing of textile materials
refers to the use of various chemical
treatments and processes to modify the
physical and chemical properties of fibers,
yarns, and fabrics.
• These treatments can improve the
aesthetics, durability, functionality, and
performance of textile materials.
• Desizing, scouring, bleaching, mercerizing,
dyeing, printing and finishing.

3. New technologies in textile chemical
processing
• Chemical processing of textiles uses large quantities of water,
electrical and thermal energy.
• The present scenario calls for the conservation of energy or usage
of low amount of energy.
• Water as solvent for chemicals is mostly used because of its
abundant availability and low cost.
• Problems associated with usage of water are effluent generation
and additional step is needed to dry the fabrics after each step.
• The amount of energy spent to remove the water is also huge
adding to the woes of processors, making processing the weakest
link among the entire textile chain.
• Various approaches on the several textile substrates have been
experimented.

4. New technologies in textile
chemical processing
• Plasma technology
• Ultrasonic technology
• Waterless dyeing
• Foam finishing
• Surface Modification using
Enzymes
• Bio finishing
• Nano technology
• Laser treatment

5. Plasma technology in textile
processing
• Plasma is a gaseous medium which can be made by using
oxygen, argon, fluorine, helium, carbon dioxide or their
mixtures.
• The basic principle behind working of plasma treatment is
modification of uppermost atomic layer of material surface by
increasing the bulk characteristics.
• This treatment gives desirable surface modifications,
including surface etching, surface activation, crosslinking,
decrystallization, and oxidation.
• Plasma treated products shows a greater affinity which not
only increase the dyeing rates of polymers but also improve
color fastness with high wash resistance of fabrics, and also
change the surface energy of fibers and fabrics.

6. Ultrasonic waves assisted
textile processing
• In recent decades, ultrasound has established an important place in different
industrial processes and has started to revolutionize environmental
protection.
• Ultrasonic represents a special branch of general acoustics, the science of
mechanical oscillations of solids, liquids and gaseous media.
• Ultrasonic frequencies lie between 20 kHz and 500 MHz (while the normal
range of human hearing is in between 16 Hz and 16 kHz).
• Cavitation is the principal physical phenomenon behind all the effects of
ultrasound in most of the treatments.
• Cavitation refer to the formation, growth and collapse of vapour or gas
bubbles under the influence of ultrasound.

7. Use of ultrasonic radiation in textile processing
• Desizing of nylon fabrics under ultrasonic
treatment results complete removal of oils used in
the size recipe while the treatment without
ultrasound shows residual oil stains.
• It was found that the use of degraded starch
followed by ultrasonic desizing could lead to
considerably energy saving as compared to
conventional starch sizing and desizing.
• Fibre degradation is also reduced and final
whiteness and wet ability of the fabric are same as
those of without ultrasonic.

8. Waterless Dyeing
• The waterless dyeing technology utilizes reclaimed CO2 as
a dye medium.
• This technology do not uses water and harmful chemicals
for dyeing. Closed loop process is used for the conversion
of CO2 into supercritical state.
• The closed loop process is patented by Dutch company
Dyecoo.
• In this process CO2 is pressurized and converted into supercritical state which is a state
which lies somewhere in between liquid, and solid state.
• The main reason behind conversion of CO2 into supercritical state is that it has high solvent
power which allows dye to dissolve very easily.
• Two American enterprises namely ColorZen and AirDye have also patented waterless dyeing
technique.

9. Foam finishing
• Conservation of water and energy has been the center of
research during the past and today also.
• Foam finishing process can be used to achieve 80 per cent
of water consumption, the energy consumption by 60-65%
in the form of gas, electricity depending upon the type of
finishing treatment used, obnoxious gases and their related
pollution can be minimized.
• The wet processing of textile materials includes highly
energy consuming operations, approximately to 80 per
cent of total energy requirement of all the operations.
• Out of this, about 66 per cent of the energy is consumed in
heating and evaporation of water from the fibres.

10. • In the foam process the liquor is diluted using the air
instead of water that is normally used to apply the
chemicals over the textile materials.
• In foam finishing, most of the water is replaced by
air, which leads to a reduction of energy
requirements in the drying processes resulting in
substantial savings in energy cost.
• Foam can be generated by mechanical air blowing,
through excess agitation or chemically by
introduction of foaming agents or combination of
these methods.
• Foam application technique can be used in the fabric
preparation, dyeing and printing, Durable press
finish, softening, soil-release finish, water, oil
repellent finish, Fire retardant finish, anti-static
finish, mercerization, etc.

11. Surface Modification using Enzymes
• Synthetic fibres have wide number of advantages such as high strength, chemical resistance, non-
shrinkage.
• But the hydrophobicity and highly crystalline structure causes discomfort to the human skin and
also generate problems in other finishing treatment such as dyeing.
• Mostly, sodium hydroxide was used to improve the hydrophillicity and flexibility of the synthetic
fibres but due to increased weight loss and yellowing of synthetic fibres makes the chemical
process unacceptable.
• To improve the hydrophillicity of synthetic materials enzymes were proven to be beneficial
alternative for surface modification.
• Cutinase enzyme has the ability to modify the surface of polyester by hydrolysis of ether bonds.
• In case of polyacrylonitrile (PAN) fibres which are more sensitive to yellowing of fibres, nitrile
hydralase and amidase were used to improve the hydrophillicity and dye absorption capacity of
PAN fibres.

12. Nano particles coating
• Nanotechnology (NT) deals with materials 1 to 100 nm in size.
• The fundamentals of nanotechnology lie in the fact that the properties
of materials drastically change when their dimensions are reduced to
nanometer scale.
Water repellency:
• Coating nano-whiskers on fabric, which are hydrocarbons.
• That create a peach fuzz effect without lowering the strength of fabric.
• The spaces between the whiskers on the fabric are smaller than the typical drop of water; water thus remains on
the top of the whiskers and above the surface of the fabric.
• However, liquid can still pass through the fabric, if pressure is applied. The performance is permanent while
maintaining breathability.

13. UV Protective Finish:
• Metal oxides like ZnO as UV-blocker are more
stable when compared to organic UV-blocking
agents.
• Hence, nano ZnO will really enhance the UV-
blocking property due to their increase surface
area and intense absorption in the UV region.
• For antibacterial finishing, ZnO nano particles
scores over nano-silver in cost-effectiveness,
whiteness, and UV-blocking property.
• Fabric treated with UV absorbers ensures that the
clothes deflect the harmful ultraviolet rays of the
sun, reducing a persons UVR exposure and
protecting the skin from potential damage.

14. Anti-static Finishes:
• Static charge usually builds up in synthetic fibers such as nylon and polyester because they
absorb little water. Cellulosic fibers have higher moisture content to carry away static charges,
so that no static charge will accumulate.
• It was determined that nano-sized titanium dioxide, zinc oxide whiskers and silane nano sol
could impart anti-static properties to synthetic fibers.
• TiO2, ZnO and ATO provide anti-static effects because they are electrically conductive
materials.
• Such material helps to effectively dissipate the static charge which is accumulated on the
fabric.
• On the other hand, silane nano sol improves anti-static properties, as the silane gel particles on
fiber absorb water and moisture in the air by amino and hydroxyl groups and bound water.

15. •Bio-finishing is performed to reduce pilling and
fuzzing from the fabric surface and improve softness,
smoothness, drapability, as well as increase fabric luster
and brightness.
• This process involves the utilization of acid cellulases to
degrade and hydrolyze the protruding cellulosic
microfibrils exist on fabric surfaces with the aid of
mechanical agitation.
• The process can be performed before, after, or during
the dyeing process, and the bio-finishing efficiency
depends on the type of cellulosic fabric and the type of
the used dyestuff.

16. Surface modification using Laser treatment
• The use of chemicals in textile processing is completely replaced by laser
technologies.
• Laser induced processing of textiles provides advantages like ease of
operation, reduced time, reduces labour cost and high efficiency.
• Laser technology is generally used for surface modification of synthetic
fibres in order to improve its performance.
• The laser irradiation over polyester fibres have improved its wettability
and air permeability.
• Argon fluoride excimer laser on nylon 6 fabrics and results showed the
rippled like structure on the irradiated area because of breaking of long
chain molecules.

17. S.
No.
Green alternative
Non eco-friendly classical
chemicals
Application in wet
processing
1 Plasma treatment Chlorination Shrink proofing
2
Combination of inorganic salts and
phosphonates
Bromated diphenyl ethers Flame retardant
3 Prereduced dyes Powder form of sulfur dyes Dyeing
4 Glucose, acetyl acetone, thiourea dioxide Sodium sulfide Reducing agents
5 Liquid ammonia Sodium hydroxide Mercerization
6 catalases Sodium thiosulfate Peroxide killer
7 Formic acid Acetic acid Neutralization agent
8 Fatty alcohol phenol ethoxylates Alkyl phenol ethoxylates Wetting agents and detergents
Eco-friendly alternative chemicals for chemical processing

18. Conclusion
• The development of various chemical processing
techniques have strengthened the concept of sustainable
textiles.
• They have made possible for processing operations to
become eco-friendly by reducing harmful impacts on
environment.
• However, the textile units located especially in
developing countries are not ready to adopt these
sustainable practices due to lack of awareness and
financial issues.
• The concerned governments and environment
protection agencies need to impose strict laws to bind
the textile industry to use green alternative chemical
and adopt aforementioned innovative processing
operation to produce sustainable materials with zero or
minimum waste productions.

19. References
• https://indiantextilejournal.com/digital-edition/special-feature/recent-developments-in-textile-wet-
processing
• Recent developments in textile dyeing techniques By: Rahul Guglani
http://www.fibre2fashion.com/industryarticle/pdffiles/12/1171.pdf
• Application of Recent Developed Techniques in Textile Wet Processing by Abu Mohammad Azmal
Morshed http://www.textiletoday.com.bd/oldsite/magazine/293
• Clean Trends in Textile Wet Processing by Dalia F. Ibrahim
http://www.textileworld.com/textileworld/features/2010/03/recent-developments-in-dyeing/
• White Biotechnology and Modern Textile Processing
http://textilelearner.blogspot.com/2013/09/recentdevelopments-in-spinning-
weaving.html#ixzz3xKT8diR8
• White-biotechnology-and-modern-textile-processinghttp://www.textileworld.com/textile-
world/dyeing-printingfinishing-2/2006/05/
• Eco friendly chemical processing of textile & environmental management by Prof. S.R. Eklahare
http://www.sulphurdyes.com/knowledgewall.html
• Shah J.N. and Shah S.R. (2013) Innovative Plasma Technology in Textile Processing:A Step towards
Green Environment Research Journal of Engineering Sciences Vol. 2(4), 34-39, April
• https://www.fibre2fashion.com/industry-article/7135/application-of-nanotechnology-in-textile-
industry
• Eid BM, Ibrahim NA, Recent Developments in Sustainable Finishing of Cellulosic Textiles
Employing Biotechnology, Journal of Cleaner Production, https://doi.org/10.1016/
j.jclepro.2020.124701.