Plasma is the fourth state of matter and can be defined as an ionized gas with a neutral total charge, consisting of electrons, ions, gas atoms and molecules in the ground or excited state.
It is a technology that modifies the surface of textile materials. Plasma is an environmentally friendly and ecological technology. In addition, features that cannot be gained by other conventional methods can be added to the textile surface. With plasma, properties such as water absorption, wetting, adhesion, dyeability, water, oil and dirt repellency and chemical resistance can be changed.
Plasma can be classified according to the temperature, pressure, particle density and degree of ionization of the gas obtained. Plasma is classified according to the temperature of the particles in it:
Plasmas in total thermodynamic equilibrium (TTD plasmas),
Plasmas in local thermodynamic equilibrium (LTD plasmas),
Plasmas that are not in local thermodynamic equilibrium (Non-LTD plasmas) are divided into three groups.
Since the temperature of the neutral atoms (the temperature of the gas) is very low (room temperature) in the Non-LTD plasmas, which are called low pressure plasmas, these plasmas are also called "cold plasmas". The plasma that is widely used in the surface modification of textile materials is cold plasma. Cold plasmas are formed in a pressure range of 0.1-0.2 torr, usually from atmospheric gases or vapors of chemical substances, in a vacuum chamber.
With plasma, modification reactions such as accumulation of chemical compounds and modification of this surface take place at the atomic level in the top layer of the textile material.
The textile material is exposed to processing between two electrodes or in an area where the plasma can act.
Hydrocarbon, fluorocarbon gases, nitrogen-containing monomers or silicon monomers are fed into the plasma chamber, which are then electronically reduced into reactive species. As a result of the interaction of the reactive species in the plasma with each other and with the substrate, accumulation occurs on the substrate surface.
There are several parameters that are effective in determining the end products of the plasma polymerization process. These; the deposition rate, the configuration of the plasma system, the reactivity of the monomer, the flow rate of the gas or monomer gas/vapor, the plasma pressure, the power, and the duration of the plasma treatment.
The most advantageous aspect of plasma polymerization in industrial processes is the prevention of chemical waste. Other advantages: Low cost, fast reaction times, low amount of chemicals and no use of water. Plasma process does not require additional processes such as wetting and drying on the fabric.
Plasma processes increase or decrease the hydrophilicity of textile materials, water repellency, dirt repellency, oil repellency, flame retardancy, antibacterial, conductivity, etc. It enables the textile surface to be modified in order to increase the adhesion between the matrix and the textile material used in composite structures and to increase the effect of the next steps such as dyeing.
As a disadvantage, a hard attitude emerges after the plasma treatment. The reason for this is that some of the covalently bonded fatty acids on the fiber surface are broken down. However, this bad effect can be eliminated by treating the textile material with a silicone-based softener.
REFERENCE
Kutlu, B., (2008) Plazma Teknolojisi Kullanılarak Çeşitli Doğal ve Sentetik Liflerin Buruşmazlık ve Güç Tutuşurluk Özelliklerinin Geliştirilmesi, Doktora Tezi, Dokuz Eylül Üniversitesi, İzmir