Thermoplastic polyetherimide glass reinforcement

Some of the common types of plastics that ate used ate thermoplastics, such as poly(phenylene sulfide) (PPS) (see Polymers containing sulfur), nylons, Hquid crystal polymer (LCP), the polyesters (qv) such as polyesters that ate 30% glass-fiber reinforced, and poly(ethylene terephthalate) (PET), and polyetherimide (PEI) and thermosets such as diaHyl phthalate and phenoHc resins (qv). Because of the wide variety of manufacturing processes and usage requirements, these materials ate available in several variations which have a range of physical properties. 

Mat and continuous glass fibre reinforcements theoretically all the thermoplastics are usable in these forms, but up to now developments have concentrated on polypropylenes (PP), polyamides (PA) and thermoplastic polyesters (PET) fibre-reinforced PEEK, polyetherimide (PEI) and polyphenylene sulfide (PPS) are used for high-performance applications. They are presented in a range of forms from stampable sheets to pellets, prepregs, ribbons, impregnated or coated continuous fibre rods. More rarely (as in the case of PA 12, for example), the thermoplastic is provided in liquid form. 

The effect of adverse environments on the fatigue behaviour of glass fibre reinforced pofymers will be discussed, taking polyetherimide (PEI) as an example [36], PEI is an amorphous thermoplastic, so a low resistance to solvents and similar harsh environments can be expected. Because of its potential applications in aircraft and railways, the hydraulic fluid (Skydrol) and the solvent methyl ethyl ketone (MEK) were chosen. 

After introducing incorporation costs, the cost of the composite may be higher or lower than that of the unfilled polymer. For low-cost commodity plastics, the term filler (implying cost reduction) may be a misnomer since manufacturing costs may offset the lower cost of most mineral fillers. For higher cost specialty high-temperature thermoplastics, the final cost of, for example, glass fiber-reinforced polyetherimide is usually less than that of the unmodified polymer. 

The most widely used and least expensive polymer resins are the polyesters and vinyl esters. These matrix materials are used primarily for glass fiber-reinforced composites. A large number of resin formulations provide a wide range of properties for these polymers. The epoxies are more expensive and, in addition to commercial applications, are also used extensively in PMCs for aerospace applications they have better mechanical properties and resistance to moisture than the polyesters and vinyl resins. For high-temperature applications, polyimide resins are employed their continuous-use, upper-temperature limit is approximately 230°C (450 F). Finally, high-temperature thermoplastic resins offer the potential to be used in future aerospace applications such materials include polyetheretherketone (PEEK), poly(phenylene sulfide) (PPS), and polyetherimide (PEI). 

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