Plastics, conducting

The furnace process involves injecting low end fraction of cmde oil, eg. Bunker Euel C, into a heated chamber. The temperature, shape of the injectors of the oil, rate of injection, and other factors are controlled to produce black fillers of different particle si2e and stmcture. The particle si2e and stmcture control the reinforcing character of the carbon black. There are 30 common grades of carbon black used in the mbber industry. There are numerous specialty grades produced, and several hundred are used in plastic, conductive appHcations, and other uses. 

From time to time attempts have been made to make plastics conductive enough to be plated directly, by immersion in the solutions in the same way as with metals. The method usually was to incorporate a conductive material, such as carbon black. 

The test method is illustrated with data in methods A and B for several plastics, conducted in six laboratories, and each test result was based on two individual determinations. The test method does not disclose liquids other than water that were used in method B. Precision of the procedure is usually fair. Some data are shown in Table 6.14. 

In order to render a plastic conductive although it is, by nature, an electrical and thermal insulator (with the exception of intrinsically conducting polymers, ICPs), we need to dope it with electrically conductive fillers such as steel microfibers (pFSs) [FEL 06], CNPs [FEL 01] or indeed carbon nanotubes [FEL 11]. By gradually varying the proportion of fillers in the polymer matrix, we see that its resistance goes... 

It has been shown that even extremely small concentrations of additives can make plastics conductive if they are in the form of conductive fibers with length to diameter (LID) ratio of 100 or more. The striking difference between the use of chunky fragments and fibrous materials in their effect on conductivity can be seen from the diagram in Figure 5.13. 

Enough carbon reinforcement can make a plastic conductive. Temperature can also dramatically affect electrical properties. 

Unlike the common plastics, conductive polymers offer a unique combination of properties that make them attractive alternatives to traditional conducting materials. Polymers, which are conducting rather than insulating, offer properties providing exciting... 

Figure 3-79. An example of Izod impact strength for various plastics, conducted at room temperature.

Applications corrosion protection, EMI shielding, filler to make plastic conductive, materials having electric conductivity, montmorillonite-PANI coated, protection against static electricity, synthesis of carbon black coated by PANI (Eonomer), synthesis of hybrid filler (multiwalled carbon nanotubes+PANI particles) plastics addition of 8-15 wt% lowers surface resistivity of plastics to 1E4-1E9 ohm coatings and inks Perento, J, Polymers in Electronics 2007, Rapra, 2007, paper 5. 

The excellent electrical conducting properties of metals are well known. Metals have resistivities in the range of 10 ohm cm compared with the resistivities of polymers which are on the order of lO ohmcm. Early studies showed there was a correlation between the electrical resistivity of the composite material and the amount of finely divided metal particles blended into it. More importantly, it was determined that a critical volume fraction of metal was required to make the plastic conductive. This critical volume or concentration is called the percolation threshold. This is the concentration at which each particle in the matrix makes contact with at least two other neighboring particles and creates a three-dimensional network in the matrix. 

Recommended for polymers Plastics (conductive filler and pigment) ... 

Figure 7 illustrates that if the dimensionless plastic conductance 77j is smaller than the base case, 77j and... 

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