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  • 11
    Electronic Resource
    Electronic Resource
    Melt-processable oligoamides having internal acetylene groups in the backbone, and thermally stable polyamides therefrom (1992)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 2645-2652 
    Details
    ISSN: 0887-624X
    Keywords: Soluble oligoamide ; internal acetylene ; crosslinking ; melt-processing ; high-temperature polymer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aromatic oligoamides of DP = 5 and 11 that have all meta-phenylene linkages were prepared by controlling the ratio of isophthaloyl chloride and diamines [m-phenylenediamine and bis(3-aminophenyl)acetylene], and then end-capped with aniline or 2-aminobiphenylene. Aromatic oligoamides having para-phenylene linkages were also prepared similarly using terephthaloyl chloride as a monomer. The oligoamides that have all m-phenylene linkages were soluble in organic solvents such as N-methyl-2-pyrrolidone and N,N-dimethylacetamide, though the oligoamides having p-phenylene linkages were much less soluble. The oligoamides having acetylene units in the backbone showed exotherm due to crosslinking. The onset of the exotherm appeared at 310-340°C for the oligoamides having all m-phenylene linkages, and 330-370°C for the oligoamides having p-phenylene linkages. They were melt-processed at 350 or 380°C for 1 h, giving tough and insoluble films from oligoamides having all m-phenylene linkages and brittle films from oligoamides having p-phenylene linkages. The films showed excellent thermal properties. For example, viscoelastic analyses showed little decrease of mechanical property up to 370°C, and Tg was not observed below the temperature. Thermogravimetric analyses also showed that thermal stability of the melt-processed films were excellent. © 1992 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1992.080301218
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  • 12
    Electronic Resource
    Electronic Resource
    High modulus polyimide/polyimide molecular composite films that utilize acetylene unit as a crosslink site (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 167-174 
    Details
    ISSN: 0887-624X
    Keywords: polyimide molecular composite ; crosslinking ; internal acetylene ; laminate processing ; high modulus ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyimide/polyimide molecular composite (MC) films comprised of a rigid polyimide derived from biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA) and a flexible polyimide derived from BPDA and bis (3,3'-diaminodiphenyl) acetylene (intA) and/or oxydianiline (ODA) were prepared by blending the polyamic acid solutions in 7 : 3 weight ratio, and then imidizing the blend films. Acetylene content in the flexible polyimide backbone was controlled by the ratio of intA and ODA. Cold-drawing of the blend polyamic acid films, followed by imidization, gives high modulus polyimide/polyimide MC films. The modulus of the MC films increased almost linearly with the draw ratio, reaching 25.5 GPa for the 40% drawn film. Acetylene groups in the flexible polyimide can be thermally cured to crosslink. The onset of exotherm appeared at 340°C on DSC, reaching maximum at 398°C. After the thermal crosslinking, the MC films maintained the high modulus, though elongation became small. Taking advantage of the crosslinkable acetylene units, two MC films were laminated and processed at 400°C for 20 min under 100 kg/cm2 to give a good-quality laminate film. The interface of the two films was strongly bonded through the crosslinking of acetylene groups. Laminate films maintained the high modulus afforded by the cold-drawing. © 1994 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320119
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  • 13
    Electronic Resource
    Electronic Resource
    Soluble polyimides that contain curable internal acetylene groups in the backbone (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 579-585 
    Details
    ISSN: 0887-624X
    Keywords: internal acetylene ; crosslinking ; soluble polyimide ; thermally curable ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320320
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  • 14
    Electronic Resource
    Electronic Resource
    Carbonization and graphitization of polyimide films: Polyamide acid methyl ester of PMDA/PDA as a precursor (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 1571-1578 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polyamide acid was prepared from pyromellitic dianhydride (PMDA) and p-phenylene-diamine (PDA) and was then reacted with NaH and methyl iodide to transform into methyl ester having various degrees of esterification. Polyamide acid methyl ester was also prepared by the polymerization between PDA and acid chloride of half-ester of PMDA. The cast films were imidized as fixed on glass substrate to give polyimide films having slightly higher tensile moduli than those from polyamide acid, suggesting that higher orientation along the film surface was achieved. It should be noted that the polyimide films prepared by the latter method from the meta-rich configuration had considerably low modulus. The polyimide films were then carbonized by heating to 900°C, and the electrical conductivity of the carbonized films was measured at room temperature. It was shown that the carbonized films from methyl ester have higher electrical conductivity than the films from corresponding polyamide acid. The carbonized films were further heated to 2800°C for graphitization, and their degrees of graphitization and orientation of the graphite crystallite as a function of esterification ratio were studied by x-ray diffraction measurement at room temperature and magnetoresistance measurement at liquid nitrogen temperature. Both measurements clearly indicate that the graphite films prepared from polyamide acid methyl ester have high degrees of graphitization and orientation. © 1996 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Carbonization of polyimide films: Effect of cold-drawing and chemical structure (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 54 (1994), S. 361-365 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polyimides of various chemical structures were prepared from pyromellitic dianhydride (PMDA), biphenyltetracarboxylic dianhydride (BPDA), oxydianiline (ODA), and p-phenylenediamine (PDA). The cold-drawn polyimide films were prepared and carbonized. The electrical conductivity of the carbonized films enhanced linearly with the draw ratio. The effect of cold-drawing on the electrical conductivity is more remarkable with the rigid polyimides such as PMDA/PDA and BPDA/PDA than the flexible polyimides such as PMDA/ODA and BPDA/ODA. The tendency is well in accord with the effect of cold drawing on the improvement of modulus of polyimides. With the rigid polyimides, the higher alignment of polymer chain is supposed to be achieved by the cold-drawing. © 1994 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070540310
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  • 16
    Electronic Resource
    Electronic Resource
    Study on the thermal stability of a chiral stationary phase coated on capillaries for GC (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 630-634 
    Details
    ISSN: 0935-6304
    Keywords: GC ; Enantiomer separation ; Thermal stability ; Chiral stationary phase ; Metal capillary column ; Glass capillary column ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A chiral stationary phase prepared by bonding L-valine-t-butylamide to XE-60 has been coated on glass and metal capillaries. The performances of the chiral glass and metal columns were equivalent to those of commercial fused silica capillary columns. The thermal stability of the glass column was examined up to 280°C. It was found that no appreciable change in separation factor (α value) was observed up to 230°C. The α values gradually decreased between 240 and 260°C, and enantiomer separation was no longer achieved at 280°C. It was concluded that the allowable upper limit temperature of the chiral stationary phase is between 230 and 240°C in the isothermal mode, and ca 260°C in temperature-programmed mode.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240181004
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  • 17
    Electronic Resource
    Electronic Resource
    Cyclodextrin carbamates as novel chiral stationary phases for capillary gas chromatography (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 179-189 
    Details
    ISSN: 0935-6304
    Keywords: Enantioselective gas chromatography ; Chiral stationary phase ; Cyclodextrin carbamate ; Hydrogen bonding interaction ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The following carbamate derivatives of cyclodextrins (CDs) were prepared as novel chiral stationary phases for capillary gas chromatography: hexakis(2,6-di-O-pentyl)-α-cyclodextrin hexa(3-n-propyl, 3-isopropyl, and 3-phenylcarbamate), heptakis-(2,6-di-O-pentyl)-β-cyclodextrin hepta(3-n-propyl, 3-isopropyl, and 3-phenylcarbamate), and octakis(2,6-di-O-pentyl)-γ-cyclodextrin octa(3-n-propyl, 3-isopropyl, and 3-isopropyl, and 3-phenylcarbamate). Metal capillary columns coated with these stationary phases resolved many kinds of racemic mixture. In general, they were especially effective towards polar compounds such as free alcohols, amines, and epoxides. The types of sample which were effectively resolved depended on the cavity size of the CD: α-CD derivatives were specifically effective toward compounds having linear alkyl chains, and β-CD derivatives toward compounds with phenyl groups. The results indicate that chiral separation with the cyclodextrin carbamates depends on the formation of inclusion complexes and also on the hydrogen-bonding interactions between the samples and the CD carbamates.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240180309
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  • 18
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    Readily processable imide oligomers containing perfluoroisopropylidene connecting units and reactive acetylenic and biphenylene groups: synthesis, curing, and thermal properties (1986)
    American Chemical Society
    Details
    Publication Date: 1986-08-01
    Print ISSN: 0024-9297
    Electronic ISSN: 1520-5835
    Topics: Chemistry and Pharmacology , Physics
    Published by American Chemical Society
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  • 19
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    Star and linear imide oligomers containing reactive end-caps: preparation and thermal properties (1986)
    American Chemical Society
    Details
    Publication Date: 1986-08-01
    Print ISSN: 0024-9297
    Electronic ISSN: 1520-5835
    Topics: Chemistry and Pharmacology , Physics
    Published by American Chemical Society
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  • 20
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    Biphenylene end-capped imide oligomers having internal acetylene groups in the backbone: preparation and thermal properties (1986)
    American Chemical Society
    Details
    Publication Date: 1986-08-01
    Print ISSN: 0024-9297
    Electronic ISSN: 1520-5835
    Topics: Chemistry and Pharmacology , Physics
    Published by American Chemical Society
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