Nonmetallic Materials and Composites at Low Temperatures

Cryogenics is an emerging technology filled with promises. Many cryogenic systems demand the use of nonmetallics and composites for adequate or increased performance. Thermal and electrical insulations, potting for superconducting magnets' mechanical sta­ bility, and composite structures appear to be some of the most significant applications. Research on nonmetallics at cryogenic temperatures has not progressed to the degree of research on metals. Nor can room temperature research be extrapolated to low tempera­ tures; most polymers undergo a phase transformation to the glassy state below room temperature. Research by producers, for the most part, has not been prac­ tical, because, except for LNG applications, the market for large material sales is not imminent. There are, however, many government­ stimulated developmental programs. Research on nonmetallics thus is dictated by development project needs, which require studies orien­ ted toward prototype hardware and specific objectives. As a result, research continuity suffers. Under these conditions, periodic topical conferences on this subject are needed. Industry and uni­ versity studies must be encouraged. Designers and project research material specialists need to exchange experiences and data. Low­ temperature-oriented research groups, such as the National Bureau of Standards and the Institute for Technical Physics - Karlsruhe, must contribute by assisting with fundamentals, interpreting proj­ ect data, and contributing to project programs through their materials research.

Contenu

Polymers.- Polymers in Low Temperature Technology (Invited).- Mechanical and Electrical Low Temperature Properties of High Polymers (Invited).- Spectroscopic Analysis of High Polymers for Use at Low Temperatures (Invited).- Correlation between Valence Energies and Low Temperature Flexibility.- Polymers - Electrical Properties.- The Dielectric Loss of Polypropylene Films and Polypropylene-Polyurethane Laminates at Cryogenic Temperatures.- Variation of Dielectric Microwave Losses in Polyethylene as the Result of Different Sample Treatments.- Dielectric Loss Spectra of Polyethylenes.- Flashover Behavior of Spacers at Low Temperatures.- Polymers - Physical Properties and Radiation Effects.- Fracture Properties of Epoxy Resins at Low Temperatures.- Interesting Low Temperature Thermal and Mechanical Properties of a Particular Powder-Filled Polyimide.- Radiation Effects on Insulators for Superconducting Magnets.- Effect of Low Temperature Reactor Irradiation on Organic Insulators in Superconducting Magnets.- Thermal Insulations.- Cryogenic Foam Insulations: Polyurethane and Polystyrene (Invited).- Durability of Foam Insulation for LH2 Fuel Tanks of Future Subsonic Transports.- Strength Specifications and Methods of Test for Structural Grades of Cryogenic Balsa Wood Insulation.- Composites - Properties of Fibers and Composites.- Carbon-Fibre-Reinforced Carbon Composites: Processing, Room Temperature Properties, and Expansion Behaviour at Low Temperatures (Invited).- Dynamic Elastic Modulus and Internal Friction in Fibrous Composites.- Compressive Fatigue Tests on a Unidirectional Glass/Polyester Composite at Cryogenic Temperatures.- Powder-Filled Epoxy Resin Composites of Adjustable Thermal Contraction.- Effect of Strain on Epoxy-Impregnated Superconducting Composites.- Thermophysical Properties of Composite Materials Based on High-Molecular Compounds with Fibrous Filler between 10 and 400 K.- Composite and Polymer Applications.- Cryogenic Applications of Composite Technology in the U.S.A. (Invited).- Properties of Plastic Tapes for Cryogenic Power Cable Insulation (Invited).- The Manufacture and Properties of a Glass Fabric/Epoxy Composite Bellows.- Laminated Fiberglass Composites for Cryogenic Structures in Underground Superconductive Energy Storage Magnets.- Selection of Materials and Manufacture of a Superconducting 0.60 MJ Pulsed Energy Storage Coil.- Application of Graphite-Epoxy to Cryogenic Telescopes.- Vacuum Impregnation with Epoxy of Large Superconducting Magnet Structures.- An Outline Design for a Cryogenic Internally Insulated Liquefied Natural Gas Pipeline for Arctic Gas Recovery.- Indexes.- Contributor Index.- Material Index.