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  • 1
    Electronic Resource
    Electronic Resource
    Crosslinkable aromatic polyimides containing 2,3-dicyanopyrazine rings (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 1303-1311 
    Details
    ISSN: 0887-624X
    Keywords: polyimides ; cyano-substituted polymers ; synthesis ; crosslinking ; thermal stability ; 2,3-dicyanopyrazine ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New crosslinkable aromatic polyimides were synthesized from 2,3-dicyano-5,6-di(aminophenyl)pyrazine (1b) and 2,3-dicyanopyrazino [5,6-9,10] diaminophenanthrene (2b). They were characterized by viscosimetry, IR, NMR, x-ray, DTA, TMA, TGA, and isothermal gravimetric analysis. The polyimides derived from 1b were amorphous whereas those prepared from 2b showed microcrystalline or crystalline character. The polymers were soluble in polar aprotic solvents (DMF, NMP, DMSO) at ambient temperature or upon heating. They dissolved also completely or partially in certain hot inorganic and organic acids (H2SO4, CCl3COOH). Their glass transition temperatures were in the range of 257-370°C. The crosslinked polymers obtained after an appropriate thermal treatment, were stable up to 397-426°C in N2 or air and afforded anaerobic char yields of 62-75% at 800°C. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1303-1311, 1997
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Synthesis and polymerization of cyano-substituted monomers derived from 4-amino-α-methyl-β,β′-dicyanostyrene (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1799-1806 
    Details
    ISSN: 0887-624X
    Keywords: cyano-substituted polymer precursors ; diamide ; diimide ; maleimide ; crosslinked polymers ; heat-resistant resins ; 4-aminoacetophenone ; malononitrile ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel class of polymer precursors of the general formula, where A is an aromatic structure bearing amide or imide linkages, were synthesized. More particularly, 4-aminoacetophenone was condensed with malononitrile to afford 4-amino-α-methyl-β,β′-dicyanostyrene (1). The condensation of the latter with half molar amount of terephthaloyl dichloride, pyromellitic dianhydride, or benzophenone tetracarboxylic dianhydride yielded the polymer precursors. In addition, compound 1 was condensed with an equimolar amount of maleic anhydride to afford the corresponding maleimide. The monomers were characterized by elemental analyses, FT-IR, 1H-NMR, and DTA. Crosslinked resins were obtained upon curing the monomers at 300°C for 72 h. They were stable up to 381-422°C in N2 or air and afforded anaerobic char yields of 64-68% at 800°C. © 1994 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321001
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis and thermal stability of the resins prepared from the reactions of 1,4-bis(2,2-dicyanovinyl)benzene with aromatic diamines and electrical conductivity of the resulting materials following pyrolysis (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1915-1921 
    Details
    ISSN: 0887-624X
    Keywords: 1,4-bis(2,2-dicyanovinyl)benzene ; thermally stable polymers ; thermosetting resins ; conductive polymers ; electrical resistivity ; cyano-substituted polymers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New thermosetting resins were prepared from the reaction of 1,4-bis(2,2-dicyanovinyl)benzene with aromatic diamines in varying molar ratios. The thermal stability of these resins was correlated with their composition and the curing conditions. They were stable in N2 up to 370-448°C and afforded anaerobic char yields of 73-84% at 800°C after curing at 300°C for 20-60 h. The temperature dependence of the electrical resistivity of all resins pyrolyzed at 700°C for 15 h was studied in the temperature range from -173-327°C (100-600 K). The results showed that at room temperature the unpyrolyzed polymers have insulating properties, whereas a dramatic decrease in the electrical resistivity is observed following pyrolysis. The temperature dependence of the electrical resistivity suggests that all of the materials studied have semiconducting properties. The observed electrical conductivity is thermally activated with activation energies ranging from 0.03-0.06 eV. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321014
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  • 4
    Electronic Resource
    Electronic Resource
    Heat-resistant resins obtained from polymer precursors bearing β,β′-dicyanovinyl terminal groups (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 1771-1778 
    Details
    ISSN: 0887-624X
    Keywords: heat-resistant resins ; cyano-substituted polymer precursors ; crosslinked polymers ; 4-hydroxy-β,β′-dicyanostyrene ; 3-amino-β,β′-dicyanostyrene ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Certain polymer precursors of the general formula: where A is an aromatic structure bearing ester, amide, azomethine, or imide linkages were synthesized. Particularly, 4-hydroxybenzaldehyde was condensed with malonitrile to afford 4-hydroxy-β,β′-dicyanostyrene which reacted with a half molar amount of terephthaloyl dichloride in the presence of an acid acceptor. In addition, 3-nitrobenzaldehyde was condensed with malonitrile to yield 3-nitro-β,β′-dicyanostyrene that was catalytically hydrogenated to the corresponding amine. The latter reacted with a half molar amount of terephthaloyl dichloride, terephthaldehyde, pyromellitic dianhydride, or benzophenone tetracarboxylic dianhydride. The polymer precursors were characterized by elemental analyses as well as IR and 1H-NMR spectroscopy. Their curing behavior was investigated by DTA. Crosslinked polymers were obtained by curing the monomers at 300°C for 24 h. They were stable up to 407-437°C in N2 and afforded an anaerobic char yield of 65-50% at 800°C. The thermal stability of resins was correlated with their chemical structures. © 1993 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080310716
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    Paper (German National Licenses)
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