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Corona Treatment
Corona treatment (sometimes referred to as air plasma) is a surface modification technique that uses a low temperature corona discharge plasma to impart changes in the properties of a surface. The corona plasma is generated by the application of high voltage to an electrode that has a sharp tip. The plasma forms at the tip. A linear array of electrodes is often used to create a curtain of corona plasma. Materials such as plastics, cloth, or paper may be passed through the corona plasma curtain in order to change the surface energy of the material. All materials have an inherent surface energy. Surface treatment systems are available for virtually any surface format including dimensional objects, sheets and roll goods that are handled in a web format. Corona treatment is a widely used surface treatment method in the plastic film, extrusion, and converting industries. History The corona treatment was invented by the Danish engineer Verner Eisby in 1951. Eisby had been asked b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Verner Eisby - Inventor Of Corona Treatment
Verner may refer to: * Verner (name), a given name and a surname (including a list of people with the name) * Verner, Ontario, a town in Canada * Verner's law, historical sound change in the Proto-Germanic language * Verner Motor, a Czech aircraft engine manufacturer **Verner JCV 360, a Czech aircraft engine design **Verner VM 133, a Czech aircraft engine design See also * Werner (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transformer
In electrical engineering, a transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple Electrical network, circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer's core, which induces a varying electromotive force, electromotive force (EMF) across any other coils wound around the same core. Electrical energy can be transferred between separate coils without a metallic (conductive) connection between the two circuits. Faraday's law of induction, discovered in 1831, describes the induced voltage effect in any coil due to a changing magnetic flux encircled by the coil. Transformers are used to change Alternating current, AC voltage levels, such transformers being termed step-up or step-down type to increase or decrease voltage level, respectively. Transformers can also be used to provide galvanic isolation between circuits as well as to couple stages of signa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Finishing
Surface finishing is a broad range of industrial processes that alter the surface of a manufactured item to achieve a certain property. Finishing processes may be employed to: improve product appearance, adhesion or wettability, solderability, corrosion resistance, tarnish resistance, the chemical resistance, the wear resistance, hardness, modify electrical conductivity, remove burrs and other surface flaws, and control the surface friction.. In limited cases some of these techniques can be used to restore original dimensions to salvage or repair an item. An unfinished surface is often called '' mill finish''. These processes can improve the durability, performance and even the appearance of the surface being finished. Surface finishing is often one of the final steps taken when working metal and is essential for guaranteeing that metal components meet the requirements of the necessary finish. Surface finishing processes can be categorized by how they affect the workpiece: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymeric Surface
Polymeric materials have widespread application due to their versatile characteristics, cost-effectiveness, and highly tailored production. The science of polymer synthesis allows for excellent control over the properties of a bulk polymer sample. However, surface interactions of polymer substrates are an essential area of study in biotechnology, nanotechnology, and in all forms of coating applications. In these cases, the surface characteristics of the polymer and material, and the resulting forces between them largely determine its utility and reliability. In biomedical applications for example, the bodily response to foreign material, and thus biocompatibility, is governed by surface interactions. In addition, surface science is integral part of the formulation, manufacturing, and application of coatings. __TOC__ Chemical methods A polymeric material can be functionalized by the addition of small moieties, oligomers, and even other polymers (grafting copolymers) ont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Activation
Plasma activation (or plasma functionalization) is a method of surface functionalization, surface modification employing plasma processing, which improves surface adhesion properties of many materials including metals, glass, ceramics, a broad range of polymers and textiles and even natural materials such as wood and seeds. Plasma functionalization also refers to the introduction of functional groups on the surface of exposed materials. It is widely used in industrial processes to prepare surfaces for bonding, gluing, coating and painting. Plasma processing achieves this effect through a combination of reduction of metal oxides, ultra-fine plasma cleaning , surface cleaning from organic contaminants, modification of the surface topography and deposition of functional chemical groups. Importantly, the plasma activation can be performed at atmospheric pressure using air or typical industrial gases including hydrogen, nitrogen and oxygen. Thus, the surface functionalization is achieved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flame Treatment
Flame treatment is the application of a gas flame to the surface of a material to improve adhesion. Polyolefins, especially polyethylene and polypropylene bond poorly, because they consist of long non- polar molecules. Without special treatment, adhesives, ink, and other coatings cannot be applied to these materials. By rapidly applying intense heat to a surface, molecular chains are broken and polar functional groups are added. Flame treatment also burns off dust, fibers, oils, and other surface contaminants. Process Flame treatment is a method where exothermic reactions between oxygen and fuel gas create thermally activated radical atoms and molecules, such as atomic oxygen (O), hydroxyl (OH), imidogen (NH), Nitric oxide (NO), and cyanide (CN). The most used gases in flame treatment are propane (C3H8), natural gas or methane (CH4), and butane (C4H10). These gases burn with atmospheric oxygen, producing water and carbon dioxide. The flame has three zones; the precombustion zo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Group
In organic chemistry, a functional group is any substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest of the molecule's composition. This enables systematic prediction of chemical reactions and behavior of chemical compounds and the design of chemical synthesis. The reactivity of a functional group can be modified by other functional groups nearby. Functional group interconversion can be used in retrosynthetic analysis to plan organic synthesis. A functional group is a group of atoms in a molecule with distinctive chemical properties, regardless of the other atoms in the molecule. The atoms in a functional group are linked to each other and to the rest of the molecule by covalent bonds. For repeating units of polymers, functional groups attach to their nonpolar core of carbon atoms and thus add chemical character to carbon chains. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidation
Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. The oxidation and reduction processes occur simultaneously in the chemical reaction. There are two classes of redox reactions: * Electron-transfer – Only one (usually) electron flows from the atom, ion, or molecule being oxidized to the atom, ion, or molecule that is reduced. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * Atom transfer – An atom transfers from one substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously, the oxidation state of oxygen decreases as it accepts electrons released by the iron. Although oxidati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron
The electron (, or in nuclear reactions) is a subatomic particle with a negative one elementary charge, elementary electric charge. It is a fundamental particle that comprises the ordinary matter that makes up the universe, along with up quark, up and down quark, down quarks. Electrons are extremely lightweight particles that orbit the positively charged atomic nucleus, nucleus of atoms. Their negative charge is balanced by the positive charge of protons in the nucleus, giving atoms their overall electric charge#Charge neutrality, neutral charge. Ordinary matter is composed of atoms, each consisting of a positively charged nucleus surrounded by a number of orbiting electrons equal to the number of protons. The configuration and energy levels of these orbiting electrons determine the chemical properties of an atom. Electrons are bound to the nucleus to different degrees. The outermost or valence electron, valence electrons are the least tightly bound and are responsible for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polarizability
Polarizability usually refers to the tendency of matter, when subjected to an electric field, to acquire an electric dipole moment in proportion to that applied field. It is a property of particles with an electric charge. When subject to an electric field, the negatively charged electrons and positively charged atomic nuclei are subject to opposite forces and undergo Electric dipole moment, charge separation. Polarizability is responsible for a material's dielectric constant and, at high (optical) frequencies, its refractive index. The polarizability of an atom or molecule is defined as the ratio of its induced dipole moment to the local electric field; in a crystalline solid, one considers the dipole moment per unit cell. Note that the local electric field seen by a molecule is generally different from the macroscopic electric field that would be measured externally. This discrepancy is taken into account by the Clausius–Mossotti relation (below) which connects the bulk behavi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric-pressure Plasma
Atmospheric-pressure plasma (or AP plasma or normal pressure plasma) is a plasma in which the pressure approximately matches that of the surrounding atmosphere – the so-called normal pressure. Fundamentals of atmospheric-pressure plasma generation A discharge can be ignited and plasma can be sustained when a DC voltage that is delivered to the gas medium via electrodes is higher than the breakdown voltage for the gas. The relationship between this breakdown voltage and the pd product—where p is the gas pressure and d is the distance between the electrodes—is referred to as Paschen's law. For a range of gas molecules, the breakdown voltage estimated by Paschen's law has a minimum value of around pd = 1-10 Torr cm. This suggests that in order to get a practical breakdown voltage for the gas discharge to ignite, a smaller electrode-gap distance is preferred as gas pressure increases. The Paschen-minimum condition at atmospheric pressure can be reached at a gap spacing of cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extrusion Coating
Extrusion coating is the coating of a molten web of synthetic resin onto a substrate material. It is a versatile coating technique used for the economic application of various plastics, notably polyethylene, onto paperboard, corrugated fiberboard, paper, aluminium foils, cellulose, non-wovens, or plastic films. It was. first developed in the 1940s for polyethylene coated paper for bags and packaging. Process Coating The actual process of extrusion coating involves extruding resin from a slot die at temperatures up to 320°C directly onto the moving web which may then passed through a nip consisting of a rubber covered pressure roller and a chrome plated cooling roll. The latter cools the molten film back into the solid state and also imparts the desired finish to the plastic surface. The web is normally run much faster than the speed at which the resin is extruded from the die, creating a coating thickness which is in proportion to the speed ratio and the slot gap. Laminating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
