Electrical properties conducting agents

Many ingredients, especially those that are conductive, may affect electrical properties. Most plastics, which are poor conductors of current, build up a charge of static electricity. Antistatic agents can be added to attract-moisture, reducing the likelihood of a spark or discharge. 

The effects of digitalis on the electrical properties of the heart are a mixture of direct and autonomic actions. Direct actions on the membranes of cardiac cells follow a well-defined progression an early, brief prolongation of the action potential, followed by a protracted period of shortening (especially the plateau phase). The decrease in action potential duration is probably the result of increased potassium conductance that is caused by increased intracellular calcium (see Chapter 14 Agents Used in Cardiac Arrhythmias). All of these effects can be observed at therapeutic concentrations in the absence of overt toxicity. Shortening of the action potential contributes to the shortening of atrial and ventricular refractoriness (Table 13-3). 

Due to unprecedented mechanical, electrical and chemical properties, CNTs have been considered as an ideal material for various applications as well as for new fundamental investigations (1,2). In this review chapter, we will only discuss mechanical and electrical properties. In most composite structures, nanotubes are used as mechanical reinforcing agents or conductive fillers. This is also the case of PVA/nanotubes nanocomposites. 

Using flexible supportive matrices and doping agents has been reported to overcome these two obstacles [15, 16]. The strategy of using dopants to reduce vulnera-bihty to electrophilic addition reactions concerns not only improvement of the electrical properties but also aims at decreasing the chemical reactivity of ECPs in general. The aromatic units would still be exposed to electrophihc aromatic substitution, but that has no critical effect on conductivity. 

The electrical conductivity of conjugated potymers is strongly influenced by the presence of doping agents and can be varied several orders of magnitude by changing the dopant concentration [135]. Further, the electrical conductivity also depends on the specific dopant. For these reasons, the discussion of the electrical properties is divided into two parts. The first part corresponds to intrinsic conduction (pristine form) and the second is devoted to doped polymers. 

The antistats can be classified as oily or waxy surface deposits. Also known are internal (glycerolmonostearates and ethoxylated secondary amines) and external (polyols) antistats. They may pose problems during sealing, printing or adhesion operations. They must accomplish functionality as mold release agents. To control the surface electrical properties, they can be used in conjunction with a conductive agent. The surface resistivity must be below lO Sicm. ... 

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