Reinforced-plastic fiber percent

TABLE 5.24 Electrical Conductivity of Reinforced Plastics 40 Percent by Weight of Fiber... 

Maleic Anhydride. Maleic anhydride is one of the fastest-growing chemical end-uses for butane. The demand in the United States was about 500 million lb in 2000. About 60 percent of the maleic anhydride produced goes into the manufacture of unsaturated polyester resins, used primarily in fiber-reinforced plastics for construction, marine, and transportation industries. It is also used to make lube oil additives, alkyd resins, fumaric and malic acids, copolymers, and agricultural chemicals. 

The terms reinforced plastics (RP) and composites refer to combinations of plastic materials and reinforcing materials, usually in fiber form (chopped fibers, porous mats, woven fabrics, continuous fibers, etc. see Fig. 7-1). Both thermoset (TS) and thermoplastic (TP) resins are used. When modern RP industry started in 1940, glass-fiber-reinforced unsaturated polyester (TS), low pressure or contact pressure, curing resins were used. Today about 60 percent of the plastics industry uses many different forms of glass fiber-polyester composites. In this chapter the abbreviation RP will be used, and in references to polyester resin it will refer only to TS, as relatively little TP polyester is used in RPs. 

The wall-thickness variations that result from such steps are always gradual, with abmpt wall thickness changes being virtually impossible. The maximum recommended thickness buildup, when necessary, is 50 percent of the normal wall thickness for the part. The following recommendations apply to designed wall thicknesses of rotational molded parts a preferred or desirable nominal wall thickness of 1/10 to in., a minimum wall thickness of 0.050 to 0.060 in., a maximum wall thickness of i in., and an optimum thickness of glass-fiber-reinforced plastic parts of f in. 

E glass—a calcium aluminosilicate with less than about 2 wt% alkali developed in the 1930s for electrical insulation applications. It has good electrical resistivity because of its low alkah content. Because of its excellent mechanical properties, its use has spread, particularly for glass-reinforced plastics. (Over 90 percent of all continuous-filament fiber is E glass.) However, it has poor acid durability. 

These are only typical values to account for many different grades, molding conditions, product shapes, wall thicknesses, and other variants. The plastics presented are basically unfilled or reinforced. GR refers to glass-fiber-reinforced compounds that usually have 10 to 40 percent, by weight, reinforcement. Other reinforcements, particularly graphite, and different fillers can result in significant different C3.TEs. 

Vetron composites of polypropylene reinforced with up to 75 percent Twintex long glass fibers (LGF) are produced by LNP Engineering, a business unit of G.E. Plastics, for exterior and underhood applications, and RTP compounds a line of LGF reinforced com-... 

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