Polymers in Electrical and Electronic Applications

The absence of polar groups along the polymer chain results in a low dielectric constant with respect to other common engineering thermoplastics. This represents a clear advantage in electric and electronic applications, but also has useful consequences in processing operations where a low moisture adsorption leads to short drying cycles (or none). 

Normally UV comes from the sun. The polymers for outdoor applications here is an example of photovoltaic module, need protection against UV radiation (Figure 6.4). In electrical and electronics applications, not only the sun but also the light can be the source of the UV radiation. For example, the modules in liquid crystal display (LCD) also need to be protected against UV radiation emitted by the back light. The fluorescent light possess specific sharp emission of UV radiation and the materials need protection against it. 

ABS is one of the most frequently used polymers in electrical and electronic equipment, as well as having widespread applications in automobiles, communication instruments, and other commodities. Recycling of ABS can be used as an aid to reducing environmental, economic, and... 

Organic polymers have attracted much interest in electrical and electronic applications because of their electrical insulating nature. Polyimides have gained much attention because of their excellent thermal stability and low dielectric constant. Polyimides have found applications in matrix resins for circuit boards, encapsulants, adhesives, passivation coatings, alpha particle barriers, ion implant masks and interlayer dielectrics."10... 

Dielectric constants of polymers vary with frequency and can either increase or decrease depending upon molecular structure, and the presence of any additives or fillers. In order to be of use in electrical and electronic applications a plastic should have reasonably constant dielectric properties over a broad range of temperatures, frequencies and humidities. It is for these reasons that materials such as polyethylene, polystyrene and the fluorocarbons find such extensive usage as electrical insulators. 

Peroxidation with peracetic acid is used to produce a number of other epoxides that are commercially available. These include epoxidized soybean oil and linseed oil used as vinyl plasticizers and hydrochloric acid scavengers in processing aliphatic halogen-containing polymers and cycloaliphatic diepoxides that are used in epoxy polymers for electrical and electronic applications. This process has also been used to make a large number of alkylene epoxides, the polymers of which have been described in the literature, but which have never reached commercial status. 

Electrical Properties. Polysulfones offer excellent electrical insulative capabilities and other electrical properties as can be seen from the data in Table 7. The resins exhibit low dielectric constants and dissipation factors even in the GHz (microwave) frequency range. This performance is retained over a wide temperature range and has permitted applications such as printed wiring board substrates, electronic connectors, lighting sockets, business machine components, and automotive fuse housings, to name a few. The desirable electrical properties along with the inherent flame retardancy of polysulfones make these polymers prime candidates in many high temperature electrical and electronic applications. 

Victrex (PES) and Radel (PAS) serve the same end uses and are, like Udel, transparent, slightly yellow polymers exhibiting heat deflection temperatures about 28°C higher than Udel PSO. Their main advantage in electrical and electronic end use is high heat resistance. They also have excellent water and chemical resistance like all polysulfones they are steam sterilizable. Electrical and electronic end uses represent the largest market segment. Applications include connectors, switches, bobbins, and sleeves. 

Modifed PTFE can be used in practically all applications, where the conventional polymer is used. In addition to that, new applications are possible because of its improved flow and overall performance. In the chemical process industry, it is used for equipment linings, seals, gaskets, and other parts, where its improved resistance to creep is an asset. In semiconductor manufacturing, modified PTFE is used in fluid handling components and in wafer processing components. Typical applications in electrical and electronic industries are connectors and capacitor films. Other applications are in unlubricated bearings, laboratory equipment, seal rings for hydraulic systems, and antistick components.103... 

Fig. 7 shows the content of low molecular weight siloxanes in the silicone polymer. As shown in the figure, almost all of the low molecular weight siloxanes can be removed from the original polymer through refining process. Nowadays, refined polymers are used for RTV rubber for electrical and electronic applications. Refined silicone sealants are used as clean room sealants in the field related to semiconductor manufacturing. 

Plastics have played critical roles in every aspect of the ongoing revolution in electronics [38-41]. They are now found in everything from computer housings and floppy discs to encapsulants and connectors. The wide range of electrical and electronic applications of polymers includes wire and cable coverings, housing adhesives, printed circuit boards and insulators (Table 7.1). 

Both electronic and medical applications of plasma polymers have been reported [54-61]. Most of these investigations are on the interface between polymers and inorganic materials, for instance, metal/polymer interfaces in structural adhesive joints, and cation diffusion along polymer/metal interfaces under an applied electric potential. In another reference, more specific aspects for electrical and electronic applications [59] were treated, wherein protective films for microcircuitry, and for wettability were explained. The use of such film for surface treatment has also been examined. 

The largest market for flame retardants is currently in electrical and electronic equipment. Almost 75% of all flame retardant polymer is used in the electrical and electronic sector. Other application sectors are wire and cable insulation, construction, offshore and marine applications, furniture, cushions, bedding, vehicles, rail and subway transport, and aerospace. A minority of FRs are also used to treat textiles, coatings and wood. 

Applications include parts in airplane and automobile engines, chemical plants, oil and gas processing equipment, and steam processing equipment. Ketone-based polymers are used in high-temperature electrical and electronic applications and medical applications. Certain resins have been used as electrical coatings and in... 

The electrical properties of the polymer are also exceptional - in many respects comparable to those of typical high performance engineering materials at room temperature, but in addition, changing little over a wide range of elevated temperatures. This is an important property, and of considerable interest when combined with high temperature capability. All of which has led to rapid acceptance of this polyetherimide in both electrical and electronic applications. 

---