Glass reinforcement elevated temperature resistance

TABLE 15.8 Elevated-Temperature Resistance of Glass-Rber-Reinforced Engineering Plastics... 

Corrosion Resistant Fiber-Reinforced Plastic (FRP). Fiber glass reinforcement bonded with furfuryl alcohol thermosetting resias provides plastics with unique properties. Excellent resistance to corrosion and heat distortion coupled with low flame spread and low smoke emission are characteristics that make them valuable as laminating resins with fiber glass (75,76). Another valuable property of furan FRP is its strength at elevated temperature. Hand-layup, spray-up, and filament-win ding techniques are employed to produce an array of corrosion-resistant equipment, pipes, tanks, vats, ducts, scmbbers, stacks, and reaction vessels for industrial appHcations throughout the world. 

Corrosion. Aqueous solutions of citric acid are mildly corrosive toward carbon steels. At elevated temperatures, 304 stainless steel is corroded by citric acid, but 316 stainless steel is resistant to corrosion. Many aluminum, copper, and nickel alloys are mildly corroded by citric acid. In general, glass and plastics such as fiber glass reinforced polyester, polyethylene, polypropylene, poly(vinyl chloride), and cross-linked poly(vinyl chloride) are not corroded by citric acid. 

Epoxy resin has a higher strength at elevated temperatures than polyester resins but is not as resistant to attack by some fluids. Some glass-reinforced epoxy-resin pipe is made with a polyester-resin hner. The coefficient of thermal expansion of glass-reinforced resin pipe is higher than that for carbon steel but mu less than that for plastics. 

Glass reinforced composites are noted for their resistance to moisture and weathering, but they tend to lost their strength in the presence of high humidity and elevated temperatures... 

PET and PBT are characterized by high strength, rigidity, and toughness low creep at elevated temperatures excellent dimensional stability low coefficient of friction good chemical, grease, oil, and solvent resistance minimal moisture absorption and excellent electrical properties. Reinforcement of these polymers with glass fibers enhances many of their properties (Table 15.16). 

Polyester resins are widely used due to their versatility and economic cost. Polyester exhibits a good combination of resistance to softening and deformation at elevated temperatures, good electrical properties and high resistance to corrosion as well as excellent weatherability [30, 31]. Structural applications, such as reinforced polyester containing glass fibre, comprise more than 80% of the market. Table 2.6 illustrates some of the physical parameters of polyester. 

Polyimide characterised by thermal and thermal-oxidative stability at elevated temperatures, chemical resistance and good mechanical properties is relatively new in the family of polymer foams [3]. In some cases, depending on the nses, additional reinforcement can be inclnded. Examples are fibre reinforced foams and syntactic foams which are composites containing hollow glass, ceramic or plastic micro-spheres dispersed throughout the polymer matrix. 

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