Static charge dissipation

Antistatic Material that minimizes static charge generation, provides controlled static charge dissipation, or both. 

Polymer blends for packaging and materials handling of electrical components would require a degree of electrical conductivity to provide for static charge dissipation. This can be achieved either by a conductive additive, such as carbon black, carbon nano-tubes or metal fibers, or via blending with a conductive polymer like polyanUine. Blending of the latter is necessary to provide flow... 

There are several other mechanisms that may lead to forces between particles. In very dry air static charge may result in Columbic interactions between particles. Columbic interactions are usually of little significance in ambient air which is usually humid enough that the static charge dissipates rapidly. In solution, nonadsorbing polymers can result in another type of weak attraction called depletion attraction. Layers of solvent molecules on particles surfaces, such as water on... 

Electrically conductive mbber (13) can be achieved by incorporation of conductive fillers, eg, use of carbon or metal powders. These mbbers exhibit volume resistivities as low as lO " H-cm. Apphcations include use in dissipation of static charge and in conductive bridging between dissimilar electronic materials under harsh operating conditions. 

Surface Resistivity. Resistance is the measure of the conductivity of a material. Conductive materials have the abiUty to dissipate static charges. Therefore, resistance is a good measure of the abiUty of an object to dissipate a static charge. Since static electricity is primarily a surface phenomenon, the resistance along the surface of the object is of most interest. 

A few percent TCNE added during formation of urethane foams imparts enough conductivity to dissipate electrostatic charges. Airplane fuel tanks filled with this foam stiU have about the same volume for fuel but do not build up static charges (29). 

Flammable liquids are considered particularly static-prone if their elec trical conductivity is within the range of 0.1 to 10 pS/m. If no particulates or immiscible liquid are present, these prodlic ts are considered safe when their conductivity has been raised to 50 pS/m or higher. Blending operations or other two-phase mixing may cause such a high rate of charging that a conductivity of at least 1000 pS/m is needed for safe charge dissipation (British Standard 5958, part 1, Control of Undesirable Static Electricity, para. 8, 1991). 

The technique of graft copolymerization is used for the production of radiation-modified fabrics and fibers. The process consists of saturating the fabrics with vinyl monomers and then irradiating it in moist state with accelerated electrons. The fabrics thus produced have improved properties such as resistance to wrinkling and shrinkage, resistance to fire, color-fastness, good launderability, and dissipation of static charge. 

Static-dissipative (antistatic) material One with an electrical resistivity that is low enough to make it incapable of accumulating hazardous concentrations of static charges when grounded. 

Anti-Static Additive - dissipates static charge in jet fuel. Static charge buildup can result in unwanted ignition of jet fuel/air mixtures. Use is normally not permitted in aviation gasoline except in Canada and Britain. Use is permitted in civil jet fuel and mandatory in military jet fuel. 

Severe hydroprocessing required to produce ultra-low sulfur fuel removes most of the polar organic compounds from the fuel. The resulting product is virtually unable to effectively dissipate static charge as it builds in moving fuel. Instead, electrical discharge into pockets of gas within a pipeline or into air and vapors as fuel is being dispensed can occur. An explosion may result. Low levels of a fuel-soluble electrical conductivity improver to ultra-low sulfur fuel can help restore fuel electrical conductivity to safe levels. 

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