Conductive plastics

For filter boxes, use flexible, conductive plastic film on surface of cake to minimize fumes... 

Anodes similar to cables are used which consist of a copper conductor covered with conducting plastic. This creates an electrolytically active anode surface and at the same time protects the copper conductor from anodic dissolution. 

The other principal thermal properties of plastics which are relevant to design are thermal conductivity and coefficient of thermal expansion. Compared with most materials, plastics offer very low values of thermal conductivity, particularly if they are foamed. Fig. 1.10 shows comparisons between the thermal conductivity of a selection of metals, plastics and building materials. In contrast to their low conductivity, plastics have high coefficients of expansion when compared with metals. This is illustrated in Fig. 1.11 and Table 1.8 gives fuller information on the thermal properties of pl tics and metals. 

Plastics are susceptible to brittle crack-growth fractures as a result of cyclic stresses in much the same way as metals. In addition, because of their high damping and low thermal conductivity, plastics are prone to thermal softening if the cyclic stress or cyclic rate is high. Examples of the TPs with the best fatigue resistance include PP and ethylene-propylene copolymers. 

Table 7-7 Applications for conductive plastics where different additives and fillers are used...

In order to accomplish with the aforementioned aim, during the first year of project, an extensive research on the different chemical additives used in six industrial sectors was conducted plastics, textiles, electronics, lubricants, leather, and paper. A list of selected chemical additives was identified for each sector and used as a study basis for the rest of the project. This is the case of the decabromo-diphenyl ether (BDE) used in electronics as a flame retardant or the triclosan used in the textile as a biocide. The results of this investigation were presented in the first volume of this book (Global Risk-Based Management of Chemical Additives I Production, Usage and Environmental Occurrence). This volume also included a section of case studies related to the selected additives in different countries (i.e., Denmark, Vietnam, Brazil, India). The main outcomes of the first part of the project are summarized below ... 

An electrode block, which included a positive NiOx electrode, a separator, made of special paper (60 am), and a negative electrode, were placed between two sheets of conductive plastic of 50-60pm thick. 

There are specific grades and masterbatches of carbon blacks especially marketed as additives for conductive plastics. It should be noted that the carbon blacks modify other properties of the polymer, especially its colour. 

Specific grades of carbon and steel fibres are especially marketed as additives for conductive plastics allowing resistivities of roughly 10 ohm.cm to be obtained. The other properties of the final material - colour, modulus, impact strength. .. are modified. Carbon fibres have a large reinforcing effect. 

Almost any substrate that will be powder coated, whether it is metal, medium-density fiberboard (MDF), or some other material, requires some kind of surface freafmenf. Surface preparafion (prefreafmenf) of wood and more specifically, MDF preparation consist of sanding, removal of confami-nanfs, and board condifioning. MDF boards fhaf will be coafed by UV curable powders should have a moisture content of 49%. If is also a common practice fo preheaf MDF boards prior to application of fhe UV powder. Mefal surfaces are always cleaned by washing and usually freated by a phosphafe primer. Conductive plastics are washed and dried and then coated without any further treatment. Nonconductive plastics are made conductive by applying a primer coat or treated by plasma or flame. ... 

Metal surfaces are always cleaned by washing and usually treated by a phosphate primer. Conductive plastics are washed and dried and then coated without any further treatment. Nonconductive plastics are made conductive by applying a primer coat or treated by plasma or by flame.38... 

The development of electrically conductive plastics is reviewed by R.B. Kaner and A.G. MacDiaimid (Set Arner. 106-111, February 1988). 

The resolution of potentiometric transducers is dependent upon the construction of the resistance element. In the case of a wire-wound resistance, in order to obtain a high resistance in a small space, the resistance wire is wound on to a mandrel or card which is straight or formed into a circle or helix depending upon the motion of the contact. This limits the resolution of the transducer as the wiper moves from one wire to the next on the mandrel. The best resolution that can be obtained is about 0.01 per cent (see Section 6.10.1). Typical wire-wound potentiometers have strokes of between 0.0025 m and 0.5 m and rotational versions from about 10° of arc to 50 turns. An alternative often employed is the conductive plastic film element. This provides a continuous resistance element and thus, a zero resolution, but such elements suffer from a higher temperature coefficient of resistance. A more recent development is a combination of earlier types in which a conductive plastic coating is sprayed on to a wire-wound resistor. 

PolyQ>phenylene sulfide) (PPS) deserves much attention as an engineering and a conductive plastic and in some cases as a specialty polymer with excellent performance. Lenz first reported that PPS is synthesized by the polycondensation of / -halothiophenolate alkali-metal salts at high temperature [83], Commercially PPS is produced by the polycondensation of -dichlorobenzene and sodium sulfide in A-methyl-2-pyrrolidone [84]. These polymerizations proceed only at high temperature and pressure, and it is difficult to remove the metal halides such as sodium chloride as by-products in order to obtain pure PPS salt contamination degrades the electric performance and moldability. 

R. I. Danescu and D. A. Zumbrunnen, Production of Electrically Conducting Plastics Composites by Three-Dimensional Chaotic Mixing of Melts and Powder Additives, J. Vinyl Addit. Technol., 6, 26-33 (2000). 

Whitaker, G., The Use of Conductive Plastic Containers in the Handling and Storage of Flammable Solvents and Powders, IBC Conference on Recent Developments in the... 

TABLE 9.8 Volume Resistivities of Metals, Conductive Plastics, and Various Insulation Materials... 

Figure 13 Schematic for a model capacitor with gel electrolyte (1) Ni wire, (2) Ni plate, (3) conducting plastic sheet, (4) gel electrolyte, (5) Teflon prop, (6) ACFC electrode, (7) Ni mesh.

Finally, only spatulas made out of conducting plastic instead of metal spatulas should be used. Furthermore, it is important to make sure that the lab equipment, and certainly the vessels for storing the energetic materials are also made out of conducting plastic and stored on a conducting surface. 

Fabrication of conducting plastics, mostly blends in which the conducting polymer is associated with another polymer that has higher mechanical properties, is probably the most developed application to day. Such polymeric blends appear to be much better solutions than carbon black-loaded... 

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