plasma treatment for textiles.ppt
TRANSCRIPT
-
Plasma treatment for multifunctional textiles PhD.eng.Visileanu EmiliaPhD.eng Ene AlexandraPhD.eng Mihai CarmenThe Research and Development Institut for Textile and LeatherBucharest - Romania
-
Finishing technologies Used to obtain products with high performancecharacteristics in order to increase :- proofing, hydrophilization, water repellency, fire retardancy, UV and bacteria resistance. Require the use of large amounts of:chemicals, water and energy.
-
Polluting industries
The effect on the environment makes the textile industry one of the most polluting industries !
-
Change structure and propertiesPhysical using different:energy sources such as plasma, laser, electromagnetic radiation, microwaves, etc.;
Chemical using different:chemicals that can change the surface or inner layers of the fibre; films: flame retardant, electrostatic charge protection , microorganism protective ;- metal deposition.
-
Plasma treatmentPlasma treatment is an innovative alternativesolution for the change of functional properties oftextiles; Material surface is modified microscopically by :- environmentally-friendly and - cost effective dry coating;This operation is possible without :- auxiliary mechanical processes or- chemicals .
-
Plasma The term plasma, was used for the first time by Irving Langmuir
Relation with biological environment;
It refers to electrically conductive ionized gas.
Plasma state of a gas - also considered as the fourth state of matter
-
Plasma enviromentPlasma environments are electrically quasineutral physical systems consistingof: electrons, ions, photons of ultraviolet radiation, free radicals, neutral moleculesObtained by: the action of high temperatures,
strong magnetic fields or electric discharge in gases.
Direct or alternative current can be used .
-
Cold plasmaCold plasma- low temperature (below 150oC) is used for :- the treatment of textile materials and fibres without :thermal degradation;
Low pressure cold plasma treatment technology - vacuum plasma technology ; Low pressure plasma technology has some advantages over the atmospheric pressure plasma :- controllable and - reproductible.
These environments have low, medium or total ionization.
-
Plasma principle
The principle of plasma treatment consists of :- putting into contact the textile material with this very reactive environment. Installations apply treatments on :- fibres, semi-finished products (sliver, roving), yarns or flat surfaces (woven, knitted fabrics, nonwoven textiles).
The following treatment can be produced at the surface of textile materials:superficial changes in the surface (cracks, roughness, micro-craters);obtaining radicals for the fibre grafting.Plasma environments can be also obtained
-
Fibre grafting
Action of the reactive groups :
-
Caracteristics The elements of the coating have to be:- firmly attached to the surface andthe layer has to have a definite degree offreedom .
This ultrathin grafted is :-first monolayer of coating, which is in contact with the surface and :-will be a guide for further coating treatmet organization.
-
Posible effectsPlasma treatments may result in changes in :the surface morphology (with effects on roughness), mass per unit area of surface and mass per unit length,some physical-mechanical properties (length density, break load, break elongation, etc), self-adherence, absorption properties andimproved comfort properties as well as improved electrical properties.
Potential applications of plasma treatment can be used in: - conventional textile products as well as in technical articles (grafting of hydrophilic polymers) and composites, waterproof articles (grafting of fluorinated polymers), fireproof articles (e.g. polyphosphonate grafting) , high conductivity articles (grafting of organic metal-containing molecules), antimicrobial, UV protection and so on .
-
Installation CD 400 Roll-to-roll The loading system is formed of:sets of trays for the treatment of fibres, semi-finished products (slivers, rovings), yarns;a complete roll winding system for flat materials: woven , knitted, nonwoven fabrics or foils. Components: Air tight chamber (plasma environment); High frequency power generator;Vacuum pumps;Gas cylinders;Electrodes;Sample holders, etc.
-
ActionsIn the airtight chamber vacuum is generated by vacuum pumps operating at a pressure in the range 10-2 to 10-3 mbar. Gas taken from the cylinder is:placed in the chamber and is ionized by a high frequency generator.
-
FeaturesA specific feature of the plasma is thevisible luminescent discharge ;The colours ranging are:- from blue-white to dark purple and are:depending on the type of gas used in theplasma installation;Highly reactive particles react with the textile material surface.
-
Industrial instalationFor vacuum plasma treatment of fabrics with the width of more than 0.6 m, :special vacuum chambers with :winding rollers with :a diameter greater than 0.3 m.Such chambers have normally three sections: - a wind, a rewind and
a plasma treatment section which are differentially supplied with plasma.
-
Tension control All special plasma treatment installations type "Roll-to-roll" use tension control of the textile material.
-
Table no.1 presents the gases used in the installation and the plasma effects on the textile surfaces.
-
Interaction with surfaces (table 3) The following notations are used: -e electron, -(s) location of an open surface, -A(s) a surface-related particle category, -B(b) a category of particles B in the whole mass and -Am is a metastable state with long lifetime
-
Table no. 4 Elements of comparison between classical finishing treatments of textile materials and treatments in plasma environment
-
Free surface energyPlasma treatments induce :changes (increases) of free surface energy of the polymers ; this resist - 200 hours since the application of the plasma treatment and :- lead to higher values compared with the untreated samples.
-
Wool knitted fabricResearch work used a wool knitted fabric, without special pretreatment.
Plasma treatment was performed in a plasma chamber of 1m3, using O2 plasma generated by a plasma generator with frequency of 40kHz, a power of 2000 to 3500 watt. Treatment times varied from 1 to 7 minutes.
-
EffectsThe most important effects observed during theresearch were: improved absorption of liquid by a factor of 100 to 1000; no significant change was observed in the mechanical properties of individual fibers; change in the mechanical properties of the yarns: - an increase yarn tenacity up to 50%; - an increase in the elongation at break of the yarn up to 250%; increase of the surface hydrophilicity by high capillarity.
-
Antifelting property and resistance to shrinkage during washing. - antifelting property and resistance to shrinkage during washing.Initial contraction of the fabric surface of 57% can be reduced tobelow 10% after plasma treatment, giving the treated material asuper-wash property.- antifelting treatment is less destructiv than the treatmentwith chemical reagents.Plasma antifelting treatment Antifelting treatment with chemical reagents
-
Healthcare application Polyester
Types of rawmaterials Cotton
-
The process for obtaining the anti-microbial products diagram:
-
ANTI- MICROBIAL TESTS
-
ANTI- MICROBIAL TESTS
-
Other advantages Lower energy consumption; Ease of adapting the process to industrial use; Reduction of water use (dry treatment processes remove rinse-spin-drying); Elimination of toxic substances.