Aircraft applications insulators

Rovings are essentially untwisted bundles of fiberglass strands wound up in parallel on cylindrically shaped packages. They are used in open lay-up moldings, woven fabrics, rods, and tubes. Woven rovings are used for open lay and press moldings. Yams [1] consist of twisted yam bundles. Weaver yarns are used for electrical and aircraft laminates, insulating tape, window shades, and filtration applications. Their major use is in printed circuit boards. Chopped strand serves as a reinforcement in a variety of markets. For example, it is used to... 

Comparing this with the best aircraft glass insulation, which has a K value of 0.039 Wm K at 6.72 kgm , shows that the Curlon has the potential for a weight savings of 33-50% in aircraft insulation and related applications. 

Expandable graphite has been used in flexible PU foams for public transport seating, in trains, buses and aircraft. Applications in the automotive sector are being examined, as are its uses in rigid PU foam for insulating materials. 

The applications for addition polyimides are for electronic/electrical materials such as printed circuit boards and insulators, as matrix resins for structural composites in aircraft and as thermal insulation materials. Recently the market for polyimide based structural composites has suffered from the termination and reduction of military aircraft programs. However, the possible emergence of the High Speed Civil Transport program (HSCT) may offer an opportunity for addition polyimides (2). 

Pyrolytic graphite was first produced in the late 1800s for lamp filaments. Today, it is produced in massive shapes, used for missile components, rocket nozzles, and aircraft brakes for advanced high performance aircraft. Pyrolytic graphite coated on surfaces or infiltrated into porous materials is also used in other applications, such as nuclear fuel particles, prosthetic devices, and high temperature thermal insulators. 

Since then, uses have shifted more toward civilian applications. Polysulfides have unusually good resistance to solvents and to the environment and good low temperature properties. This makes them particularly useful in a variety of sealant applications. For example, the outstanding resistance of polysulfides to petroleum (qv) products has made them the standard sealant for virtually all aircraft integral fuel tanks and bodies. Another important application is in insulating glass window sealants (qv). Sealants based on liquid polysulfides have had an excellent record since the 1950s and are the worldwide market leader in this application. 

Worldwide production capacity of liquid polysulfides is about 33,000 t with manufacturing sites in the United States, Japan, and Germany. Total consumption is about 28,600 t. Approximately 50% is for insulating glass sealants, 30% for construction applications, and 10% for aircraft sealants. In addition, 909 t of the solid polysulfide rubbers are sold each year. 

Polyimide and Melamine. These are both low density, essentially open-cell foams used as pipe insulations, particularly those involved with fluids operating at temperatures up to 530 K. Because these foams operate at higher temperatures and have improved flammability characteristics compared to other foams, they are also used for some aircraft and marine applications. 

Flame Resistance. Traditionally, small-scale laboratory flammability tests have been used to initially characterize foams (38). However, these do not reflect the performance of such materials in bulk form. Fire characteristics of thermal insulations for building applications are generally reported in the form of qualitative or semiquantitative results from ASTM E84 or similar tunnel tests (39). Similar laiger scale tests are used for aircraft and marine applications. 

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