7,075 research outputs found

    An improved processible acetylene-terminated polyimide for composites

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    The newest member of a family of thermosetting acetylene-substituted polyimide oligomers is HR600P. This oligomer is the isoimide version of the oligomer known as HR600P and Thermid 600. Although both types of material yield the same heat resistant end products after cure, HR600P has much superior processing characteristics. This attributed to its lower melting temperature (160 + or - 10 C, 320 + or - 20 F) in contrast to 202 C (396 F) for Thermid MC-600, its longer gel time at its processing temperature (16 to 30 minutes bvs 3 minutes), and its excellent solubility in low boiling solvents such as tetrahydrofuran, glymes, or 4:1 methyl ethyl ketone/toluene mixtures. These advantages provide more acceptable coating and impregnation procedures, allow for more complete removal at lower temperatures, provide a longer pot life or working time, and allow composite structure fabrication in conventional autoclaves used for epoxy composite curing. The excellent processing characteristics of HR600P allow its use in large area laminated structures, structural composites, and molding compositions

    Study of the effects of ethylene oxide-freon 12 upon properties of polymers and metallic surfaces Final report, 10 Oct. 1964 - 31 Mar. 1966

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    Physical, mechanical, and electrical tests to determine the effects on polymeric products after exposure to ethylene oxide-Freon 1

    Literature review of mechanisms of interaction of ethylene oxide and organic and inorganic materials

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    Mechanism of interaction of ethylene oxide and polymeric and inorganic compound

    New hyperthermal thermosetting heterocyclic polymers

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    Polyimidazopyrrolone polymers, formed by the condensation of aromatic dianhydrides with aromatic tetraamines in various solvents, form moldings that resist degradation in air and retain great strength at 400 to 700 degrees F. The resins have good insulating properties, are easy to mold, and make good protective coatings

    Material processing with hydrogen and carbon monoxide on Mars

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    Several novel proposals are examined for propellant production from carbon dioxide and monoxide and hydrogen. Potential uses were also examined of CO as a fuel or as a reducing agent in metal oxide processing as obtained or further reduced to carbon. Hydrogen can be reacted with CO to produce a wide variety of hydrocarbons, alcohols, and other organic compounds. Methanol, produced by Fischer-Tropsch chemistry may be useful as a fuel; it is easy to store and handle because it is a liquid at Mars temperatures. The reduction of CO2 to hydrocarbons such as methane or acetylene can be accomplished with hydrogen. Carbon monoxide and hydrogen require cryogenic temperatures for storage as liquids. Noncryogenic storage of hydrogen may be accomplished using hydrocarbons, inorganic hydrides, or metal hydrides. Noncryogenic storage of CO may be accomplished in the form of iron carbonyl (FE(CO)5) or other metal carbonyls. Low hydrogen content fuels such as acetylene (C2H2) may be effective propellants with low requirements for earth derived resources. The impact on manned Mars missions of alternative propellant production and utilization is discussed

    Design and testing of vibration absorbing oceanographic cable terminations

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1995.by Ethan L. Butler.M.S

    The Student's World

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    Commencement address given by Howard Landis Bevis, President of The Ohio State University, to the Spring 1941 graduating class of The Ohio State University, Ohio Stadium, Columbus, Ohio, June 16, 1941

    The Challenge of Deferment

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    Commencement address given by Howard L. Bevis, President of The Ohio State University, to the Spring 1951 graduating class of The Ohio State University, Ohio Stadium, Columbus, Ohio, June 8, 1951
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