Composite fabric

Composites Fabrication, Composites Eabricators Association, Arlington, Va., pubHshed monthly. 

Unsaturated polyester resins predominate among fiber-reinforced composite matrices for several reasons. A wide variety of polyesters is available and the composites fabricator must choose the best for a particular appHcation. The choice involves evaluation of fabrication techniques, temperatures at which the resin is to be handled, cure time and temperature desked, and requked cured properties (see Polyesters, unsaturated). 

Ease of cure, easy removal of parts from mold surfaces, and wide availabiHty have made polyesters the first choice for many fiber-reinforced composite molders. Sheet mol ding compound, filament winding, hand lay-up, spray up, and pultmsion are all weU adapted to the use of polyesters. Choosing the best polyester resin and processing technique is often a challenge. The polyester must be a type that is weU adapted to the processing method and must have the final mechanical properties requked by the part appHcation. Table 1 Hsts the deskable properties for a number of fiber-reinforced composite fabrication methods. 

Fig. 3. Load—deflection curve for a SiC—C—SiC composite in four-point bending. Note the extreme change in behavior fora composite fabricated with a 0.17-p.m carbon layer between the SiC fiber and the SiC matrix as compared with a composite with no interfacial layer (28).

The above data represent the first from composites fabricated with fixed catalyst VGCF. A review of the data leads to the conclusion that the thermal and electrical properties of this type of carbon fiber are perhaps the most likely to be exploited in the short term. While mechanical properties of the composites are not as attractive as the thermal and electrical, it may be noted that no effort has... 

Composites fabricated with fixed catalyst VGCF can be designed with fibers oriented in preferred directions to produce desired combinations of thermal conductivity and coefficient of thermal expansion. While such composites are not likely to be cost-competitive with metals in the near future, the ability to design for thermal conductivity in preferred directions, combined with lower density and lower coefficient of thermal expansion, could warrant the use of such VGCF composites in less price sensitive applications, such as electronics for aerospace vehicles. 

Composites fabricated with the smaller floating catalyst fiber are most likely to be used for applications where near-isotropic orientation is favored. Such isotropic properties would be acceptable in carbon/carbon composites for pistons, brake pads, and heat sink applications, and the low cost of fiber synthesis could permit these price-sensitive apphcations to be developed economically. A random orientation of fibers will give a balance of thermal properties in all axes, which can be important in brake and electronic heat sink applications. 

In order for VGCF to be suecessfully incorporated into engineering composites, it must be available in forms which composite fabricators are equipped to handle. Since VGCF is bulky and discontinuous as produced, it is not amenable to the textile processing used for continuous carbon and glass fiber. Thus fiber... 

S.W. Lim, Y. Nishida, "Superplasticity of whisker reinforced 2024 aluminium alloy composites fabricated by squeeze casting" Scr. Metall Mater. 32, 1911, 1995... 

Yoshimura M, Suchanek W (1997) In situ fabrication of morphology-controlled advanced ceramic materials by Soft Solution Processing. Solid State Ionics 98 197-208 Yu S-H, Yoshimura M (2002) Feriite/metal composites fabricated by soft solution processing. Adv Funct Mater 12 9-15... 

Laurence J Craigie, B S>Chem. Composite Resources, LLC industry consultant in regulatory, manufacturing, and business needs for the composite industry Member, American Society of Mechanical Engineers (Chairman RTP Corrosion Resistant Equipment Committee) Member, American Society of Testing and Materials Member, National Association of Corrosion Engineers International Member, Composite Fabricators of America (received President s Award) (Reinforced Thermosetting Plastie)... 

Epoxy (Amine-Cured) Bisphenol A-based epoxy resins used for composite fabrication are commonly cured with multifunctional primary amines. For optimum chemical resistance these generally require a heat cure or postcure. The cured resin has good chemical resistance, particularly to basic environments, and can have good temperature resistance. 

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