Electrostatic dissipation

Electrical Properties. (See Table 1.) A new family of ABS products exhibiting electrostatic dissipative properties without the need for nonpolymeric additives or fillers (carbon black, metal) is now also commercially available (2). 

Because TF1V Fluoroplastic is highly flexible, resistant to chemicals and automotive fuels, and has good barrier properties, it is used as a permeation barrier in various types of flexible hose in automotive applications and in the chemical process industry. Liners and tubing can be made from an electrostatic dissipative grade of TFIV, which is sometimes required for certain automotive applications.60... 

PP/EVAc blends are immiscible, thus in two-component systems only a small amount of EVAc can be used, e.g., to improve dyeability, flexibility, electrostatic dissipation, or barrier properties. The hydrolyzed EVAc (EVAl) was also used [Minekawa ei al., 1969]. In most cases the PP/EVAc blends are part of more a complex, multicomponent system comprising a reactive compatibilizer (see Table 1.50). 

Polymer blends have been often used as electrical insulating materials. Polymers do not readily conduct electrical current, are inexpensive in comparison to other known insulating materials, are sufficiently durable and heat resistant. However, in some applications, owing to the accumulation of surface charge that may discharge rapidly and cause damage to electronic components, cause fires or explosions, they may pose problems. A need has existed for electrostatic dissipating polymeric compositions, ESD. 

The ESD compositions must have sufficient resistivity to cause slow dissipation of a static charge, but not too low as to allow the charge to move too quickly through the material, thereby causing an arc or spark. The surface resistivity 10 < R 10 Q. cm is considered desirable. Attempts have been made to coat an electrostatic dissipative material onto plastic, add graphite, or metal particles, but coating can easily be wiped out and the additives are expensive, make... 

Most polymers have high electrical resistivity, are inexpensive in comparison to other known insulating materials are heat resistant and sufficiently durable. Owing to their sensitivity to oxidation and solvents, they are frequentiy blended to generate better electrical insulating alloys. In the past two decades, there has been serious elfort to modify the electrical properties of polymers and their blends. The electrically conductive polymers can be broadly categorized as (i) electrostatic dissipating polymeric compositions, and (ii) electrically conductive polymer blends. Utracki has reviewed evolution of these materials [Utracki, 1998]. 

The electrostatic dissipating polymeric compositions (ESD) are developed to overcome problems related to the accumulation of surface charge and its rapid discharge leading to shocks, fire, explosions and damage to electronic components, etc. 

These compositions must provide surface resistivity 10 < R < 10 (Qcm). The early efforts, to achieve the optimum surface resistivity, such as coating the polymeric parts with electrostatic dissipative materials, addition of either graphite, metal particles or fibers, incorporation of low molecular weight antistatic agents etc., did not yield fruitful results [Kozlowski, 1995]. Antistatic properties are observed for materials having either -SH or -OH groups e.g., phenolic, alcoholic, or acidic). 

For document handling applications, there are several components for which PAB s are suited. These include bases and chassis, which require high modulus pen bodies and optical devices, which require excellent dimensional stability moving parts that require lubricity and wear resistance and paper paths that require electrostatic dissipation (BSD). Similar requirements occur for related components in computers. Electromagnetic Interference (EMI) shielding is required for computer enclosures and printed circuit boards. Among the more common PAB s specified for these applications are PC/ABS and PPE/PS. 

Performance, Electrostatic dissipation 89, 325, 972 see also ESD Performance, Environmental stress cracking resistance see ESCR... 

There are a variety of potential applications of carbon nanotube (CNT) reinforced thermoplastic composites in automotive industry and systems involving electrostatic dissipation (ESD) and EMI. 

A second key function for adhesives is to form ohmic contacts or electrical connections between active and passive devices, connectors, leadffames, I/O leads, or other electronic parts to form a circuit. Other applications for electrically conductive adhesives include electrostatic dissipation and electrical grounding connections. 

Numerous other types of electrically conductive polymer composites are commercially available but are beyond the scope of this chapter. These materials are used in such applications as conductive inks [1], thermoplastic molded monolithic objects for electrostatic dissipation (ESD) [2] and electromagnetic interference (EMI) shielding applications [3], and a wide variety of other applications, including heating elements, switches, transducers, and batteries [2]. Similarly, the fabrication of conductive polymer materials via metal vapor deposition or electrodeposition onto polymer surfaces will not be discussed here. 

ESD electrostatic dissipation or discharge F fluoride, formaldehyde, phosphate, etc. 

Due to the exceptional properties of carbon nanotubes (CNTs), such as high electrical and thermal conductivity and excellent mechanical properties, they are expected to have great potential as fillers for polymeric matrices. CNTs are incorporated in electrically insulating polymer materials to achieve electrostatic dissipative behavior or electrical conductivity and improved mechanical properties. Current applications for such nanocomposites include electrostatically dissipative plastic housing or fuel lines, as well as lightweight and electrostatically paintable plastic components replacing metals in car panel applications. Incorporation of CNTs in polymers on an industrial scale is... 

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