Gabriel Synthesis

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The Experts below are selected from a list of 984 Experts worldwide ranked by ideXlab platform

Jetze J. Tepe - One of the best experts on this subject based on the ideXlab platform.

Manasi Keni - One of the best experts on this subject based on the ideXlab platform.

Lon J Mathias - One of the best experts on this subject based on the ideXlab platform.

  • Solid-state NMR characterization of copolymers of nylon 11 and nylon 12
    Solid state nuclear magnetic resonance, 1997
    Co-Authors: C. G. Johnson, Lon J Mathias
    Abstract:

    Solid-state 13C and 15N NMR spectroscopy, in conjunction with differential scanning calorimetry, wide-angle X-ray diffraction and infrared spectroscopy, were used to characterize a series of nylon 11 and 12 copolymers with mole percentages of nylon 12 monomer of 0, 15, 35, 50, 65, 85, and 100%. Monotonic melting point (Tm) and heat of fusion depressions were observed for the copolymer series with the 65 mol% nylon 12 copolymer having the lowest apparent crystallinity and Tm at 148 degrees C. Solid-state 15N NMR spectra showed a smooth shift of the main peak position for the as-prepared copolymers from 84 ppm for the alpha-form of pure nylon 11 to 89 ppm for the gamma-form of pure nylon 12. Similar behavior was seen for FTIR amide V and VI modes which are also sensitive to the alpha- and gamma-crystal forms. 13C NMR T1 measurements showed that the overall most mobile sample was the 65:35 copolymer. The amide group of the 1:1 copolymer was labelled using 15N-labelled amino acids available through the Gabriel Synthesis; an annealed, solution-cast film of this sample showed a T1N value of 349 s, similar to values seen for annealed nylon 11 and nylon 12 homopolymers. The WAXS pattern for the 65 mol% nylon 12 sample showed a sharp peak at 2 theta = 21.3, overlapping a broad peak centered at 2 theta = 21.0. These are consistent with the values seen for gamma-form nylon 12. The 1:1 copolymer (15N labelled) was shown to be polymorphic, like the homopolymers after specific treatments, with a gamma-like phase formed upon solvent casting, and an alpha-like phase dominating for as-polymerized material and precipitated flakes.

  • Synthesis and Characterization of Copolymers of Nylon 11 and Nylon 12
    1993
    Co-Authors: C. G. Johnson, Lon J Mathias
    Abstract:

    Abstract : A series of copolymers was prepared from 11-aminoundecanoic and 12- aminododecanoic acids by melt-condensation at 210 degree C in sealed tubes under vacuum. Mole percentages of nylon 12 monomer were 0, 15, 35, 50, 65, 85, and 100 percent in the feed. The amide group was labelled using nitrogen 15-labelled amino acids available through the Gabriel Synthesis (only the 1:1 copolymer was enriched with nitrogen-15). Solid-state carbon 13 (at 100.6 MHz) and nitrogen 15 (at 20.3 MHz) NMR spectroscopy, differential scanning calorimetry, wide-angle x- ray diffraction, and infrared spectroscopy were used to characterize the copolymers. Solid-state nitrogen 15 NMR spectra showed a smooth shift of the main peak position from 84 ppm for alpha-nylon 11 to 89 ppm for gamma-nylon 12 for the as-prepared copolymers. Similar behavior was seen from amide V and VI modes which are sensitive the alpha- and gamma-crystal forms. Carbon-13 NMR T1 measurements showed that the most mobile sample was the 63:35 nylon 11-co-12 polymer

C. G. Johnson - One of the best experts on this subject based on the ideXlab platform.

  • Solid-state NMR characterization of copolymers of nylon 11 and nylon 12
    Solid state nuclear magnetic resonance, 1997
    Co-Authors: C. G. Johnson, Lon J Mathias
    Abstract:

    Solid-state 13C and 15N NMR spectroscopy, in conjunction with differential scanning calorimetry, wide-angle X-ray diffraction and infrared spectroscopy, were used to characterize a series of nylon 11 and 12 copolymers with mole percentages of nylon 12 monomer of 0, 15, 35, 50, 65, 85, and 100%. Monotonic melting point (Tm) and heat of fusion depressions were observed for the copolymer series with the 65 mol% nylon 12 copolymer having the lowest apparent crystallinity and Tm at 148 degrees C. Solid-state 15N NMR spectra showed a smooth shift of the main peak position for the as-prepared copolymers from 84 ppm for the alpha-form of pure nylon 11 to 89 ppm for the gamma-form of pure nylon 12. Similar behavior was seen for FTIR amide V and VI modes which are also sensitive to the alpha- and gamma-crystal forms. 13C NMR T1 measurements showed that the overall most mobile sample was the 65:35 copolymer. The amide group of the 1:1 copolymer was labelled using 15N-labelled amino acids available through the Gabriel Synthesis; an annealed, solution-cast film of this sample showed a T1N value of 349 s, similar to values seen for annealed nylon 11 and nylon 12 homopolymers. The WAXS pattern for the 65 mol% nylon 12 sample showed a sharp peak at 2 theta = 21.3, overlapping a broad peak centered at 2 theta = 21.0. These are consistent with the values seen for gamma-form nylon 12. The 1:1 copolymer (15N labelled) was shown to be polymorphic, like the homopolymers after specific treatments, with a gamma-like phase formed upon solvent casting, and an alpha-like phase dominating for as-polymerized material and precipitated flakes.

  • Synthesis and Characterization of Copolymers of Nylon 11 and Nylon 12
    1993
    Co-Authors: C. G. Johnson, Lon J Mathias
    Abstract:

    Abstract : A series of copolymers was prepared from 11-aminoundecanoic and 12- aminododecanoic acids by melt-condensation at 210 degree C in sealed tubes under vacuum. Mole percentages of nylon 12 monomer were 0, 15, 35, 50, 65, 85, and 100 percent in the feed. The amide group was labelled using nitrogen 15-labelled amino acids available through the Gabriel Synthesis (only the 1:1 copolymer was enriched with nitrogen-15). Solid-state carbon 13 (at 100.6 MHz) and nitrogen 15 (at 20.3 MHz) NMR spectroscopy, differential scanning calorimetry, wide-angle x- ray diffraction, and infrared spectroscopy were used to characterize the copolymers. Solid-state nitrogen 15 NMR spectra showed a smooth shift of the main peak position from 84 ppm for alpha-nylon 11 to 89 ppm for gamma-nylon 12 for the as-prepared copolymers. Similar behavior was seen from amide V and VI modes which are sensitive the alpha- and gamma-crystal forms. Carbon-13 NMR T1 measurements showed that the most mobile sample was the 63:35 nylon 11-co-12 polymer

Bruno Jousselme - One of the best experts on this subject based on the ideXlab platform.

  • Amino functionalized thin films prepared from Gabriel Synthesis applied on electrografted diazonium salts
    Journal of electroanalytical chemistry and interfacial electrochemistry, 2012
    Co-Authors: Fanny Hauquier, Serge Palacin, Nabila Debou, Bruno Jousselme
    Abstract:

    A new diazonium salt bearing an aliphatic primary amine protected with a phthalimide group has been synthesized and isolated from the reaction of the corresponding aniline derivative with NOBF4 in acetonitrile. Electrochemical grafting of this compound in potentiodynamic conditions on vitreous carbon or on gold form thick, stable, adherent and insulating polyphenylene-like films on the electrode surface. Treatment with hydrazine of these polymers cleaves the imide functions to release amine groups prone to subsequent immobilization of molecules, biomolecules or particles via a covalent amide linkage. That primer polyphenylene-like layer establishes a good electrical communication between the surface of the electrode and the immobilized probes

  • Amino functionalized thin films prepared from Gabriel Synthesis applied on electrografted diazonium salts
    Journal of Electroanalytical Chemistry, 2012
    Co-Authors: Fanny Hauquier, Serge Palacin, Nabila Debou, Bruno Jousselme
    Abstract:

    International audienceA new diazonium salt bearing an aliphatic primary amine protected with a phthalimide group has been synthesized and isolated from the reaction of the corresponding aniline derivative with NOBF4 in acetonitrile. Electrochemical grafting of this compound in potentiodynamic conditions on vitreous carbon or on gold form thick, stable, adherent and insulating polyphenylene-like films on the electrode surface. Treatment with hydrazine of these polymers cleaves the imide functions to release amine groups prone to subsequent immobilization of molecules, biomolecules or particles via a covalent amide linkage. That primer polyphenylene-like layer establishes a good electrical communication between the surface of the electrode and the immobilized probe

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