Electrostatic discharge compounds

Lead styphnate. Lead styphnate, 13, also known as 2,4,6-trinitro-soreinate, is an explosive compound used to start the ignition-to-detonation process in the explosive sequence. It is stable at elevated temperatures and non-corrosive. The addition of graphite enhances its electrical conductivity in systems designed for electrical initiation. Dry lead styphnate is the most sensitive of the primary explosives to electrostatic discharge [6]. 

Antistatics (electrostatic-discharge dissipating (BSD)) Dissipation of static charges Mostly amines, quaternary ammonium compounds, phosphate (organic), and polyethylene glycol esters (PFG)... 

There is a rising demand for conductive or electrostatic discharge (BSD) compounds in the electronics industry for packaging and handling purposes and for use in semiconductors and disc drives. New flexible plastic displays will be produced in large munbers to show video images. 

Carbon fibers, 1/2 in. in length, are being evaluated widely in injection molding applications, and a few commercial compounds for EMI applications (phenolics, nylon) have been introduced commercially. Carbon fibers are presently being used for electrostatic discharge and electrostatic painting applications. 

Conductive additives such as high-purity carbon blacks are commonly added to compounds where there is a potential hazard from electrostatic discharge. There is also extensive development of systems based on metal fibres, to give higher protection or shielding against electromechanical interference. 

These compounds have a resistivity in the region of 10 -10 Q/sq and are designed for use where slow and controlled dissipation of static charges is required. EMI shielding compounds, for protection of electronic components from electrostatic discharge, offer a surface resistivity of lower than 10 i2/sq, with volume resistivity of lower than 1 cm and up to 55 dB attenuation. 

Free 5-azidotetrazole is reported in Fedoroff, Sheffield, and Kaye s encyclopedia as less sensitive to impact than its alkaline salts [1], Other authors reported 5-azidotetrazole as a highly sensitive compound [2, 77]. Stierstorfer et al. [77] reported sensitivity to impact below 1 J, sensitivity to friction below 5 N, and sensitivity to electrostatic discharge 2.2 mJ. 5-Azidotetrazole melts and decomposes at 165 °C when heated with heating rate 5 °C min [77]. Pure 5-azidotetrazole is fairly stable in storage. However, it may spontaneously explode in presence of some impurities especially in presence of traces of acetic acid (it can explode even in acetone solution explosions do not occur in aqueous or ethanol solutions) [1]. 

The sensitivity of CP to shock, electrostatic discharge, and hot wire noticeably depends on its form. It is relatively insensitive to these stimuli in bulk form (practically comparable to secondary explosives). However, in the pressed state, CP is as sensitive as primary explosives. This behavior is the main advantage of this compound [4]. 

Extremely important for the safe handling of such pyrotechnic mixtures are, in addition to the chemical stability (computability with the binder and other additional compounds) particular the thermal stability and the lowest possible impact, friction and electrostatic sensitivities. Figure 2.18 shows an example of a DSC thermogramm (Differential Scanning Calorimetry), which shows that the new environmentally friendly red mixture (colorant components from Figure 2.17) is thermally stable up to approx. 260 °C. But the sensitivity of the mixture towards electrostatic discharge (BSD) was lowered to 1 J (cf. typical values for the human body are within the range 0.005-0.02 J). 

The sensitivity of mercury fulminate to percussion is one of the compound s most advantageous characteristics. Mercury fulminate is highly sensitive to electric spark. A spark from a person charged to less than 5,000 volts causes ignition. This condition is possible in plant operations. The sensitivity to electrostatic discharge is reported to be 0.025 to 0.07 joules. 

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