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  • Articles: DFG German National Licenses  (80)
  • Chemistry  (80)
  • General Chemistry  (28)
  • 1
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of fluorinated poly(aryl ether ketone)s containing 1,4-naphthalene moieties (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 521-526 
    Details
    ISSN: 0887-624X
    Keywords: poly(aryl ether ketone) ; naphthalene derivatives ; fluorinated ; Ullmann ether synthesis ; Friedel-Crafts acylation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The new monomer 2,2-bis[4-(4-{4-fluorobenzoyl}-1-naphthoxy)phenyl]hexafluoropropane (2) was synthesized in a two-step reaction sequence. 2,2-his[4-(1-naphthoxy)phenyl]-hexafluoropropane (1) was prepared using the Ullmann ether synthesis reaction of 4,4-(hex-afluoroisopropylidiene)diphenol with 1-bromonaphthalene. Friedel-Crafts acylation of 1 with 4-fluorobenzoyl chloride in methylene chloride containing dimethylsulfone selectively afforded 2 in 82% yield. The polycondensation of 2 with various bisphenols in DMAc in the presence of an excess of potassium carbonate as a condensation reagent was carried out at 165°C to quantitatively afford the corresponding fluorinated poly(aryl ether ketone)s containing 1,4-naphthalene moieties. Thermal analysis of the polymers showed them to have Tgs ranging from 194 to 230°C and to be thermally stable in air up with initial weight losses at about 500°C. In addition, these novel polymers exhibited excellent solubility in organic solvents including NMP, DMAc, and chloroform. © 1997 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Druckentwicklung im Schmierspalt eines Stift-Scheibe-Tribometers (1979)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 10 (1979), S. 361-366 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Development of Film Pressure in a Pin-on-Disk TribometerIn a Pin-on-disk machine with “parallel surfaces” the load carrying capacity can be increased by additional oscilating normal forces. A formula for the calculation of the filmpressure was developed and the results were compared with those of other authors.
    Notes: Bei parallelen Gleitflächen läßt sich durch Überlagerung dynamischer Normalkräfte eine beträchtliche Tragfähigkeitssteigerung erzielen. Eine Formel zur Bestimmung des Druckverlaufs im Schmierspalt wird abgeleitet; die Ergebnisse werden mit den Rechenergebnissen anderer Autoren verglichen.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19790101008
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  • 3
    Electronic Resource
    Electronic Resource
    Liquid crystalline poly(enamine ketone)s formed through hydrogen bonding (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 33 (1994), S. 71-77 
    Details
    ISSN: 0959-8103
    Keywords: Hydrogen bonding ; Liquid crystal ; Model compound ; Poly(enamine ketone)s ; 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: A series of poly(enamine ketone)s (PEAKs) which exhibit liquid crystalline phases has been synthesized. The enamine ketone groups are able to exist in the cis and trans conformations. Molecular modelling results show that the cis conformation is energetically more favorable due to intramolecular hydrogen bonding. Model compound studies indicate that the formation of the mesogen requires the cis conformation in the enamine ketones to stabilize the liquid crystalline phase. This liquid crystalline phase is nematic for the model compound and the polymers. The heats of liquid crystal transition in the model compound and in PEAKs are very close (4.7 kJ/mol in model compound and 4.0 kJ/mol of repeating units in polymers). This is not only an indication of a similar percentage of the cis conformation in both cases, but also an example that the flexible ethyleneoxy spacers in the polymers do not contribute to the orientational order of this liquid crystalline phase. PEAKs can crystallize through either quenching from the isotropic melt or from the liquid crystalline phase. Crystallization kinetics exhibit the effect of pre-ordering when these two different kinetics are compared.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210330108
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis and properties of fluorinated polyimides and fluorinated poly(imide amide)s containing pendent cyano groups (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 33 (1994), S. 399-407 
    Details
    ISSN: 0959-8103
    Keywords: polyimide ; poly(imide amide) ; cyano ; fluorinated ; dielectric constant ; relative humidity ; 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: A series of fluorinated polyimides and fluorinated poly(imide amide)s containing pendent cyano groups were prepared and investigated to determine their dielectric constants as a function of relative humidity and thermal characteristics. The fluorinated polymides and fluorinated poly(imide amide)s containing pendent cyano groups were prepared by reaction of bis(4-aminophenoxy) benzonitriles with a fluorinated dianhydride and with a fluorinated di(acid chloride) containing preformed imide rings. The properties of the fluorinated polyimides and fluorinated poly(imide amide)s containing pendent cyano groups were compared with those of fluorinated polyimides and fluorinated poly(imide amide)s prepared from 1,3-bis(4-aminophenoxy)benzene. The introduction of the pendent cyano groups caused an increase in the dielectric constant and an increase in the glass transition temperature of the polymers compared with the polymers prepared without pendent cyano groups.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210330410
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  • 5
    Electronic Resource
    Electronic Resource
    Phase structure, morphology and phase boundary diagram in an aromatic polyimide (BPDA-PFMB)/m-cresol systemPresented at ‘MacroAkron '94, 35th IUPAC Symposium on Macromolecules’, Akron, Ohio, 11-15 July 1994. (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 37 (1995), S. 207-214 
    Details
    ISSN: 0959-8103
    Keywords: polyimide ; m-cresol ; phase structure ; morphology ; phase boundary diagram ; gel/sol transition ; DSC ; polarized light microscopy ; 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: An organo-soluble aromatic polyimide has been synthesized from 3,3′, 4,4′-bis(phenyltetracarboxylic) dianhydride (BPDA) and 2,2′-bis (trifluoromethyl)-4,4′-diaminobiphenyl (PFMB) via a one-step polymerization in m-cresol. The phase boundary diagram for this system has been established by differential scanning calorimetry, polarized light microscopy (PLM) and wide angle X-ray diffraction (WAXD) experiments. A crystallosolvate form I has been found over the entire concentration region at low temperatures. When the temperature is increased, an isotropic phase has been observed below concentrations of about 40%. In the relatively high concentration region between 45 and 95%, a transition from the crystallosolvate from I to a crystallosolvate form II has been observed. Form II exhibits a different WAXD pattern. In a narrow concentration region between the isotropic and the crystallosolvate form II (40-45%), a biphase behavior has been found. The birefringence of this region may be an indication of a liquid crystalline phase. The BPDA-PFMB polymer crystal has been found in the very high concentration region (〉95%) for temperatures 〉250°C. The morphologies of these phases have been investigated via PLM and transmission electron microscopy. Above the gel/sol transition temperature, the form I shows negative birefringent spherulites consisting of thin lamellae. The form II exhibits a tendency of positive birefringent spherulites. Possible mechanisms of the formation of the metastable phase morphology and their associations with the mechanical gel/sol transition are also discussed.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1995.210370309
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  • 6
    Electronic Resource
    Electronic Resource
    Modification of polyethylene terephthalate (dacron) via denier reduction: Effects on material tensile strength, weight, and protein binding capabilities (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Biomaterials 6 (1995), S. 289-299 
    Details
    ISSN: 1045-4861
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Thrombosis remains a significant and potentially catastrophic complication of polyethylene terephthalate (Dacron) prosthetic vascular graft implantation. Numerous attempts have been made to create a novel surface that reduces the adverse effects of blood interaction with the material. The purpose of this study was to create reactive groups on Dacron without significantly altering the chemical and physical properties of the biomaterial. These groups would then serve as “anchor sites” for covalent attachment of the blood protein albumin to the surface, thus creating a more biocompatible surface. Denier reduction, an established textile chemistry procedure that creates carboxyl groups on the fiber surface via hydrolysis of the material, was performed at 100°C using sodium hydroxide concentrations of 0.5, 1.0, 2.5, and 5.0% (treated materials referred to as 0.5% hydrolyzed etc.). Tensile strength determination of hydrolyzed materials revealed no statistically significant difference in material strength between control, 0.5, and 1.0% hydrolyzed materials; the 2.5 and 5.0% hydrolyzed materials had significant strength loss as compared to the controls. Significant fiber weight loss occurred in the 1.0, 2.5, and 5.0% hydrolyzed Dacron segments. The 0.5% hydrolyzed material did not have any significant weight loss. Covalent linkage of 125I-albumin to these modified materials using the crosslinker 1-ethyl-3-(3-dimethyl aminopropyl)-carbodiimide hydrochloride (EDC) resulted in the 0.5% hydrolyzed material having the greatest protein binding (330 ng/mg Dacron, 2.4-fold greater than control). Incubation of the 0.5% hydrolyzed material with EDC and various concentrations of 125I-albumin resulted in the 14.80 m̈M solution permitting the greatest binding per milligram Dacron (330 ng/mg Dacron). Scanning electron microscopy, performed blindly, revealed no change in the 0.5% hydrolyzed Dacron as compared to untreated Dacron. The 5.0% hydrolyzed Dacron, however, had noticeable structural damage on the outer periphery of the fiber surface. Observation of the untreated Dacron with nonspecifically bound albumin showed scattered areas of albumin adherent to the fiber surface whereas covalent linkage of albumin to the 0.5% hydrolyzed Dacron via EDC crosslinking showed numerous albumin moieties on each fiber. This study demonstrates that a clinically accepted biomaterial (Dacron) can be chemically modified, without significantly altering the physical and chemical characteristics of the biomaterial, in order to covalently bind albumin to the fiber surface. Thus, these results serve as foundation for creating potential novel biomaterials without significantly altering the properties of the original biomaterial. © 1995 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jab.770060410
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of new aromatic poly(ether ketone)s (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 56 (1995), S. 1397-1412 
    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: A general method for the preparation of aromatic poly(ether ketone)s containing amide, amide-imide, cyano, oxadiazole, and pyridazine moieties has been developed. Polymerization is based on a ketone-activated halide displacement from amide-, amide-, imide-, cyano-, oxadiazole-, or pyridazine-containing bis(4-fluorobenzoyl) moieties by bisphenoxides in a polar aprotic solvent. The bis(4-fluorobenzoyl) moieties were prepared by reaction of 4-fluorobenzoyl chloride with diphenoxy monomers containing amide, amide-imide, cyano, oxadiazole, or pyridazine groups under modified Friedel-Crafts conditions in methylene chloride. All of the polyether ketones prepared were amorphous and exhibited Tgs ranging from 134 to 218°C. In addition, films of the aromatic polyether ketones displayed good thermal stability and flexibility. The dielectric constants of the films were characterized as a function of relative humidity (RH). © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070561103
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  • 8
    Electronic Resource
    Electronic Resource
    Long-term hydrostatic strength characteristics of thermoplastics pipe (1966)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 6 (1966), S. 285-295 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: A method for developing long-term hydrostatic design stresses, defined as the estimated tensile stress in the wall of the pipe in the circumferential orientation due to internal hydrostatic pressure that can be applied continuously with a high degree of certainty that failure of the pipe will not occur, for thermoplastic pipe materials is described. The background information used to develop this method, data to confirm its validity, and several of its more important peculiarities are presented and discussed. The method treats hydrostatic stress-failure time test results by the method of least squares with time as the dependent variable. The long-trem performance of thermoplastic pipe materials is evaluated by stresses calculated for periods of 100,000 hours (11.43 years) and 50 years.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760060403
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  • 9
    Electronic Resource
    Electronic Resource
    The origin of β relaxations in segmented rigid-rod polyimide and copolyimide films (1993)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 33 (1993), S. 1373-1380 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: Most aromatic polyimides and copolyimides show a β relaxation process below their α relaxation processes in dynamic mechanical and dielectric measurements. The origin of this β relaxation has been under active discussion. In order to gain a better understanding of the origin of the β relaxation process, the dynamic mechanical behavior of a series of segmented rigid-rod polyimide and copolyimide films with different dianhydrides and diamines has been systematically studied. For some of the polymers, crystallinity and orientation effects on the β relaxation process were also investigated. It is found that the β relaxation process in the unoriented films can mainly be attributed to a relatively noncooperative motion in uncrystallized diamines. However, this noncooperative nature may be gradually lost by increasing the crystallinity and orientation. Molecular modeling and computation have led to a discussion of possible diamine motion in the β relaxation process.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760332102
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  • 10
    Electronic Resource
    Electronic Resource
    Quantitative determination of airbone C1- and C2-halocarbons by GC/ECD (1988)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 11 (1988), S. 51-56 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Air analysis ; Airborne halocarbons ; Chlorocarbons ; Electron capture detector ; Forest decline ; Halocarbons ; Thermodesorption ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The atmospheric levels of C1- and C2-halocarbons are determined by trapping on an adsorbent, thermodesorption, cryofocussing, gas chromatographic separation on a thick-film capillary, and electron-capture detection. The various aspects relevant to reliability and accuracy are discussed, such as type of adsorbent, range of detector response, and levels of contaminants present in blanks. These in turn have implications for optimum sample size and amount of adsorbent. The adopted method is suitable for routine analysis of airborne halocarbons at variable locations. The air concentrations of C1- and C2-halocarbons on the ground of mountain forests are similar to those in cities, a fact which supports the hypothesis that chlorocarbons are involved in the initiation of a phytotoxicological phenomenon commonly referred to as “forest decline”.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240110114
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