Glass-fiber reinforced epoxy resin Materials

Perhaps the most dramatic effect of interfadal adhesion on material properties is found with glass fiber reinforced epoxy resins. Both the glass and the epoxy are brittle materials with a resistance to cracks less than lOOJm". But when the two brittle materials are combined by mixing glass fibers into liquid epoxy, followed by polymerizing the resin to solidify it, then the crack resistance... 

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. 

The relevant properties of these materials for the torsional-mechanical analysis are listed in Table 8.11. On the basis of specific elastic modulus and specific shear modulus, the best materials are the graphite-fiber-reinforced epoxy resin, followed by either of the alloys, then the Kevlar fiber-reinforced epoxy. The chopped glass sheet molding compound is obviously not a good choice. 

Kunz and Kirschning developed a chemically functionalized monolithic material which is based on a glass/polymer composite [28,29] (refer to Sect. 3.1). This material is available in different shapes including rods, disks, and Raschig rings. The polymeric phase of this composite was chemically functionalized (e.g., substitution of the benzylic chlorine by trimethylamine or sulfonation). Rod-shaped objects were first embedded in a solvent-resistant and shrinkable PTFE tube. This was followed by encapsulation with a pressure-resistant fiber-reinforced epoxy resin housing with two standard HPLC fittings, which created... 

High performance composites may be laminates wherein veils of carbon fiber ate treated with an epoxy resin, stacked up to the desired final product thickness, and then laminated together under heat and pressure (see Composite materials Carbon and graphite fibers). Simply mixing together carbon or glass fibers and polymeric resins to form a reinforced plastic leads to a composite material, but this is not a laminate if not constmcted from discrete phes. 

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... 

Hidemitsu Hojo et al. (Hidemitsu et al., 1998) reviewed the behavior, the forms and mechanisms of corrosion of resins and glass fiber reinforced plastics under several aqueous solutions. They concluded that the concept of the corrosion rate of metals could be applied even in plastics and fiber reinforced plastics for each corrosion form. The corrosion resistance of the composites is mainly dependant on the resin s corrosion resistance properties and the corrosion crack propagation. Applications requiring corrosion resistant composite materials usually use epoxy and polyester resin as the composite matrix because these thermosets have high resistance to chemical attack. Among the various type of resins epoxies dominate the... 

Materials with highly cross-linked epoxy resin reinforced with woven fiber glass are the most common in use. Bromine is reacted with the epoxy matrix and is used to provide fire retar-dancy. Most epoxy-based materials satisfy the Underwriters Laboratories (UL) classification of V-0 for fire retardancy. The generic term for this family of epoxy resin materials is FR-4, with FR standing for flame retardant and 4 an assigned number indicating epoxy. Epoxyfiberglass materials are sold by many snpphers and have become a commodity material. 

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