Electrical properties glass fiber reinforcement

Some electrical properties of reinforcing fibers, composite resins, and the resulting composites are given in Tables 6.12, 6.13, and 6.14, respectively. These values should be taken as approximate only, especially for the composites, since fiber orientation, content, and field strengfh have an enormous impacf on fhe dielecfric properties of these materials. Some of the most widespread electrical applications for glass-fiber-reinforced epoxy systems are in printed circuit boards and electrical housing such as junction boxes. 

Table 6.12 Some Electrical Properties of Selected Reinforcing Glass Fibers...

Table 6.14 Some Electrical Properties of Selected Glass-Fiber-Reinforced Resins...

Tetrabromobisphenol A is used in epoxy resins especially for glass fiber reinforced used in printed circuit board. Nonreactive compounds such as tetrabromophatalate ester, bis(tribromophenoxy) ethane, and decabromodiphenyl ether are also used. The use of synergists, such as antimony oxide, reduces the quantity of brominated flame retardant necessary but decreases the electrical properties required. 

As mentioned earlier, suspensions of particulate rods or fibers are almost always non-Brownian. Such fiber suspensions are important precursors to composite materials that use fiber inclusions as mechanical reinforcement agents or as modifiers of thermal, electrical, or dielectrical properties. A common example is that of glass-fiber-reinforced composites, in which the matrix is a thermoplastic or a thermosetting polymer (Darlington et al. 1977). Fiber suspensions are also important in the pulp and paper industry. These materials are often molded, cast, or coated in the liquid suspension state, and the flow properties of the suspension are therefore relevant to the final composite properties. Especially important is the distribution of fiber orientations, which controls transport properties in the composite. There have been many experimental and theoretical studies of the flow properties of fibrous suspensions, which have been reviewed by Ganani and Powell (1985) and by Zimsak et al. (1994). 

Components of switches, relays, and connectors use glass fiber reinforced semicrystalline polymers, such as PA, PPS, PBT, and PET. The following requirements are important in these applications dimensional stability and precision, low moisture absorption, strength, resistance to creep, electrical insulating properties, and resistance to high working temperatures ( 85°C). 

The electrical SHM of composites refies on the material itself to act as the sensor. Carbon fibers are electrically conductive the epoxy resin is an insulator. The CFRP composite is somehow conductive because the densely packed carbon fibers may touch each other. As damage (e.g., cracks and delamination) takes place in the composite, the electric conductivity is expected to change. The glass fiber-reinforced polymer (GFRP) composite is a nonconductive insulator with certain dielectric properties. Damage in GFRP composites creates microcracks and even... 

Such glass fiber-reinforced composites based on the unsaturated polyester thermosets are usually fabricated as sheet molding compounds (SMC) and bulk molding compounds (BMC). These are widely used in various metal replacement applications because of their cost-effectiveness, rigidity, light weight, and corrosion resistance properties particularly useful in transportation (cars and trucks), constmction, pipe, and tank applications. Automotive and tmck body panel and strucmral component applications of SMC include doors, hatchbacks, hoods, front grilles, etc. Some nonautomotive applications of SMC and BMC include sanitaryware (bathtubs, shower stalls, sinks), appliances, business machine, and electrical components. 

The mechanical, physical, thermal, and electrical properties of two common glass fiber reinforcements for plastics, E and R, are listed in Table 9.3 (19). The tensile strength given in this table is the virgin fiber strength. In a separate publication... 

Keywords glass fiber (GF), composition, physical properties, chemical resistance, electrical properties, optical properties, glass fiber production, glass fiber reinforced composites. 

Polyphenylene sulfide (glass fiber reinforced) 91 13.8 0.6 N/A 0.031 Hexural strength, modulus Electrical properties, notched Izod... 

EFFECT OF GLASS FIBER REINFORCEMENT ON ELECTRICAL PROPERTIES OF POLYMERS... 

In Table 5.9 the mechanical, thermal, and electrical properties of virgin and 20% glass fiber-reinforced perfluoroalkoxy ethylene are compared. 

PET/PBT blends are usually glass fiber reinforced, show a good set of mechanical properties and dimensional stability. They have found use in appliances, as well as for electrical and automotive... 

Diallyl phthlates (DAP) and diallyl isophthlates (DAIP) are the principal thermosets in the allyl family, with DAP used predominantly. They are used for glass-preimpregnated cloth and paper that must undergo a heat, time, and pressure cycle to produce parts. Molding compounds are reinforced with fibers to improve their mechanical and physical properties. Glass fibers impart mechanical performance, acrylic fibers provide improved electrical performance, polyester fibers enhance impact resistance, and other fibers and fillers can impart different performance traits. 

Since glass fiber reinforcement improves the impact resistance of SPS, GFSPS becomes competitive with other engineering plastics with the excellent balances of mechanical and electrical properties, heat resistance, and dimensional stability (Table 13.4). 

Kaolin is primarily used in the rubber industry as a filler and is frequently used in the calcined form. It is being widely used in innerliner compound in the tubeless tire industry. Use of kaolin in glass fiber reinforced thermosets improves surface quality, reduces warpage, and lowers crack formation. Kaolin is used in polyvinyl chloride (PVC) wire coating because of its good electrical insulating properties. Surface-treated calcined kaolines are used for tire wheel cap made from polyamides (PA) and greenhouse films from LDPE [7[. 

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