Electrostatic shocks

Electrostatic shocks Eliminated at high moisture conrenr. Increased at low moisture contciu, causing discomfort to occupants and damage to electronic components. High explosion risk. 

Electrostatic shocks Electric shocks experienced by occupants due to a static discharge. Increasing the humidity and using non-static materials reduce the frequency of such events. 

While the development of PEDOT-based antistatic layers started in the early 1990s, a few years later PEDOT PSS hard coatings were developed for cathode ray tubes (CRT). The outer surface antistatic layer was used to avoid electrostatic shocks and dust contamination during manufacture and use (Figure 10.28). Such antistatic layers were previously made by sputtering a thin layer of indium-doped tin oxide (ITO). It therefore appeared to be highly... 

Explosives are commonly categorized as primary, secondary, or high explosives. Primary or initiator explosives are the most sensitive to heat, friction, impact, shock, and electrostatic energy. These have been studied in considerable detail because of the almost unique capabiUty, even when present in small quantities, to rapidly transform a low energy stimulus into a high intensity shock wave. 

Fig. 5.1. The electrostatic configurations of the Neilson-Benedick three-zone model describe a piezoelectric solid subject to elastic-inelastic shock deformation which divides the crystal into three distinct zones. Zone 1, ahead of the elastic wave, is unstressed. Zone 2 is elastically stressed at the Hugoniot elastic limit. Zone 3 is isotropically pressurized to the input pressure value (after Graham [74G01]).

Sensitivity to mechanical, electrostatic and thermal shock is typical of a primary explosive. 

Although thermal decomposition (and runaway) is often identified with the inherent reactivities of the chemicals involved, it must be emphasized that hazards can arise from induced reactions as discussed in Chapter 2. These induced reactions may be initiated by heat, contamination, or mechanical means (e.g., shock, friction, electrostatic spark). 

Gilbert and Voreck synthesized hexakis(azidomethyl)benzene (HAB) (45) from the reaction of hexakis(bromomethyl)benzene (44) with sodium azide in DMF. This azide has been comprehensively characterized for physical, thermochemical and explosive properties and stability. HAB is a thermally and hydrolytically stable solid and not highly sensitive to shock, friction or electrostatic charge but is sensitive to some types of impact. It shows preliminary... 

While electrostatic precipitators have relatively high collection efficiencies (99-100%) over a wide range of particle sizes ( 0.05-5 /im), there are a number of disadvantages. These include the lack of size information, particle reentrainment due to sparking, and practical problems such as high cost and shock hazards. As a result, they have not been widely used in ambient air studies. 

Any compd or mixt whose heat of formation is smaller by 500 J/g (or more) than the sum of the heats of formation of its reaction products must be regarded with suspicion and handled with more than usual care. The hazards involved in working with a potentially expl system are directly proportional to the amount and to the rate of energy release. Because the reaction kinetics cannot be predicted, the propensity of a new system for expl reaction must be determined. The sensitivity of the system can be evaluated by means of impact, friction, shock and electrostatic discharge. Appropriate methods are reviewed in the Experimental and Hazard Assessment section of this article. Sensitivity to heat or elevated temp may be evaluated by use of differential thermal analysis (DTA)... 

See under Sensitivity to Flame, Heat, Sparks, Electrostatic Discharges, etc 1 )Sensitivity to Initiation by Heat. See under Sensitivity to Flame, Heat, Sparks, etc as)Sensitivity to Initiation by Influence. See Detonation by Influence Test n)Sensitivity to Rifle Bullet Impact. See Bullet Impact Sensitiveness Test o)Sensitivity to Shock. See Impact Sensitivity Test pfSensitivity to Sparks. See under Sensitivity to Flame, Heat, Sparks, Electrostatic Discharges, etc Sensitivity to Sympathetic Detonation. See Detonation by Influence Tests... 

Previously reported [2] as a non-melting solid exploding on attempted purification, this proved a very shock sensitive (40 kg/cm) solid of m.p. 150°C. Less sensitive to electrostatic discharge and friction. Methods of explosibility testing for very small quantities of very sensitive materials are described [1]. 

The isolated acid or its salts are shock- and heat-sensitive explosives [1]. Safe preparative procedures have been detailed [2]. Anhydrous salts should be handled only in small quantities and shielded from electrostatic discharge. Although names reflecting the preparation from azide are still in use (2005) the actual structure of the salts and disulfide derives from the cyclic l,2,3,4-thiatriazole-5-thiol, and the tautomeric thiatriazolidinethione forms the isolable free acid [3]. The heavy metal salts, though powerful detonators, are too sensitive for practical use [2]. 

Great care has to be taken in the preparation of pentazole compounds. Pentazoles are extremely sensitive toward shock, friction, temperature, light, and electrostatic impact. This is true even for the most stable pentazoles, while less stable pentazoles like />-nitrophenylpentazole exploded at every attempt at their isolation. Several explosions of pentazoles without apparent reason have also been reported, especially for large-scale preparations. Thus appropriate safety measures (protection of face, ears, body, and hands) have to be taken at all times during these reactions. The smallest possible amounts should be used <1994HOLJ796>. 

Pure methyldichlorosilane does not inflame by shock however, it immediately inflames by contact with minium, lead dioxide, copper and silver oxides. Pure trichlorosilane does not self-inflame in air (excluding the possibility of spark formation by electrostatic charge) neither does it self-inflame by shock. However, since technical trichlorosilane almost always contains dichlorosilane SiH2Cl2 (the boiling point is 8.3 °C), capable of self-inflaming by shock, trichlorosilane can also inflame by shock. Thus, if technical trichlorosilane contains more than 0.2% of dichlorosilane, one should avoid shocks and pushes when it contacts air. 

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