20,680 research outputs found

    Ladder polymers for use as high temperature stable resins or coatings

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    An object of the invention is to synthesize a new class of ladder and partial ladder polymers. In accordance with the invention, the new class of ladder and partial ladder polymers are synthesized by polymerizing a bis-dienophile with a bis-diene. Another object of the invention is to provide a fabricated, electrically conducting, void free composite comprising the new class of the ladder and partial ladder polymers described above. The novelty of the invention relates to a new class of ladder and partial ladder polymers and a process for synthesizing these polymers. These polymers are soluble in common organic solvents and are characterized with a unique dehydration property at temperatures of 300 to 400 C to provide thermo-oxidatively stable pentiptycene units along the polymeric backbone. These polymers are further characterized with high softening points and good thermo-oxidative stability properties. Thus these polymers have potential as processable, matrix resins for high temperature composite applications

    Synthesis of linear, double chain, ladder polymers from substituted tetraphosphonitriles Quarterly progress report, Jun. - Aug. 1966

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    Synthesis of linear, double-chain, ladder polymers from substituted tetraphosphonitrile

    Synthesis of linear, double chain, ladder polymers from substituted tetraphosphonitriles Quarterly report, Sep. - Nov. 1966

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    Synthesis of linear, double chain ladder polymers from substituted tetraphosphonitrile

    Synthesis of linear, double chain ladder polymers from substituted tetraphosphonitriles Annual report, 3 May 1965 - 2 May 1966

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    Synthesis of linear, double-chain ladder polymers from substituted tetraphosphonitrile

    Temperature dependent photoluminescence of organic semiconductors with varying backbone conformation

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    We present photoluminescence studies as a function of temperature from a series of conjugated polymers and a conjugated molecule with distinctly different backbone conformations. The organic materials investigated here are: planar methylated ladder type poly para-phenylene, semi-planar polyfluorene, and non-planar para hexaphenyl. In the longer-chain polymers the photoluminescence transition energies blue shift with increasing temperatures. The conjugated molecules, on the other hand, red shift their transition energies with increasing temperatures. Empirical models that explain the temperature dependence of the band gap energies in inorganic semiconductors can be extended to explain the temperature dependence of the transition energies in conjugated molecules.Comment: 8 pages, 9 figure

    Molding process for imidazopyrrolone polymers

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    A process is described for producing shaped articles of imidazopyrrolone polymers comprising molding imidazopyrrolone polymer molding power under pressure and at a temperature greater than 475 C. Moderate pressures may be employed. Preferably, prior to molding, a preform is prepared by isostatic compression. The preform may be molded at a relatively low initial pressure and temperature; as the temperature is increased to a value greater than 475 C., the pressure is also increased
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