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  • Chemistry  (25)
  • Conducting polymers  (2)
  • 1990-1994  (24)
  • 1945-1949  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 275-280 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Tetrachlorophthalic anhydride (TCPA) was reacted with cellulose diacetate and with cellulose diethyl ether in dioxane solution to produce esters with rather low tetrachlorophthalyl contents. Phthalic anhydride was found to be considerably more reactive than was TCPA with these cellulose derivatives, especially if pyridine was used as the reaction solvent. Acylations could not be executed with TCPA in the presence of pyridine as solvent, however, because this material decomposed the anhydride, removing chlorine from it. The TCPA derivatives were more limited in solubility than were the corresponding esters made from phthalic anhydride.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Collagen-silicone composites were fabricated and tested for biocompatibility by subcutaneous implantation in rats. The silicone component consisted of addition cure or condensation cure sheets. The collagen component was either (a) a sponge layer 2 mm thick, (b) a thin film 12-20 μm thick, or (c) residual collagen bonded to or incorporated in the silicone rubber. Collagen sponges were mechanically bonded to silicone sheets, and collagen thin films and residual collagen were physically and chemically attached to epoxyderivatized silicone sheets. Analysis of implanted samples showed that reduced capsule formation occurred around collagen spongesilicone, compared to control silicone sheets. Only where the underlying silicone sheet, or interpenetrating silicone, was exposed to the tissue, did limited capsule formation occur. In contrast, thin capsule developed completely around silicone coated with a thin collagen film and around silicone bonded to residual collagen. Sponge-silicone composites and control silicone sheets were free of acute and chronic inflammation, except for occasional foreign body giant cells in sponge adjacent to silicone. Silicone coated with micron-thick collagen films exhibited some inflammation, but residual collagen-silicone did not. This study suggests that, to prevent capsule formation, a collagen coat must be of minimum thickness and surface coverage sufficient to prevent any contact between silicone and tissue. © 1992 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 35 (1994), S. 197-205 
    ISSN: 0959-8103
    Keywords: polyaniline ; inverse chromatography ; thin layer chromatography ; amino acids ; characterisation of chemical interactions ; 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: Inverse thin layer chromatography is used to characterise the chemical interactions that occur on polyaniline that has been electrochemically deposited on to a support. Amino acids are used as the molecular probe species by which the retention behaviour can be related to particular chemical interactions. The mobile phase is also varied, with respect to its polarity and pH, in order to add a further dimension to the qualitative information that is obtained. Anion exchange interactions are found to be the dominant interaction type. However, the behaviour seems to be different to that which occurs on conventional anion exchange materials. The behaviour was dependent upon the number of negative sites and also their spatial arrangement. A configurational-selective ionic interaction with the polaron lattice of the polyaniline is proposed. The response of the anion exchange behaviour to a change of pH suggested that protonated sites remained within the polymer, even at high pH values (c 9).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: An analytical strategy for quantifying the diffusion of 18O in small, melt-grown single-crystal Yba2Cu3O7-x superconductors by image depth profiling SIMS is presented. This technique was used to obtain data for both in-depth (along the c-axis) and lateral (in theab-plane) diffusion from one superconducting crystal. Cross-sectional images, generated from the image depth profiling data, revealed features of the diffusion processes that would not have been apparent in a standard depth profile. Retrospective selected area depth profiling was used to remove the influence of background species, edge effects and imperfections in the crystals, resulting in processed depth profiles with greater dynamic range. These techniques also were used to study the diffusion behavior of fluorine that was unexpectedly incorporated into the superconduting crystals during preparation. Finally, the influence of detector artifacts on the analytical results was evaluated.
    Additional Material: 13 Ill.
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  • 5
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The relatively low levels of human salivary proteins in whole saliva as compared to the ductal secretions may be related to their interaction with oral bacteria. These interactions are thought to play an important role in the microbial colonisation of the mouth, and salivary proteins adsorbed to oral surfaces have been implicated in adherence. In this study we attempted to investigate the prevalence of interactive strains by screening a range of oral bacteria. Parotid saliva was incubated with bacterial suspensions and consequent alterations to the salivary protein profile determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). A number of salivary components were found to be preferentially removed, particularly by those species known to be primary colonisers of clean tooth surfaces.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Brookfield, Conn. : Wiley-Blackwell
    ISSN: 0193-7197
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Plastisol rheological characteristics are of prime importance to the formulator and processor. As the formulas become more complicated, interactions can occur between ingredients that have significant effects on rheology. This paper explores aspects of the resin-CaCO3 filler interaction. Experiments investigating some of the effects of resin-filler interaction on rheological behavior have been performed. The experiments indicate that particle size distributions of the resin and filler, as they relate to packing efficiency, have a significant effect on rheological behavior, especially at high filler concentrations. The effects of particle packing vs. oil absorption are also investigated and discussed.
    Additional Material: 6 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Advanced Materials 6 (1994), S. 798-802 
    ISSN: 0935-9648
    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
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    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: Injectable collagen is a concentrated dispersion of collagen fibers in aqueous solution that is used to correct dermal contour defects through intradermal injection. The effect of hydrophobic forces on the rheology of concentrated dispersions of collagen fibers was studied by dynamic rheological measurements over temperatures ranging from 283 to 308 K. The results are interpreted in terms of the associated relaxation time spectra and the theory of Kamphuis et al. for concentrated dispersions. Increases in fiber rigidity are seen from a progressive decrease in the slope of the linear log G′ (or G″) vs. log ω data recorded for these dispersions as temperature is increased. A molecular interpretation of this result was obtained by treating collagen fibers as a liquid crystalline phase of rigid-rod collagen molecules that have phase-separated from aqueous solution. Hydrophobic forces affect the volume fraction of water that is present in the phase-separated fibers, which, in turn, affects the rigidity of the fibers. Distinct yielding behavior (in the nonlinear viscoelastic region) occurs at temperatures above 293 K and reflects a gel transition. Thermal gelation of collagen dispersions is proposed to proceed through hydrophobically driven mechanisms of increased fiber rigidity and enhanced interfiber attractive forces. © 1993 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
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  • 9
    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: The effects of thermal and mechanical fatigue on the flexural strength of G40-600/PMR-15 cross-ply laminates with ply orientations of (02, 902)2s and (902, 02)2s are examined. The relative improtance of shear and tensile stresses is examined by varying the span-to-depth ratios of flexural test specimens from 8 to 45 Acoustic emission singals are measured during the flexural tests in order to monitor the initiation and growth of damage. Optical microscopy is used to examine speciments for resin cracking, delamination, and fiber breaks after testing. Transverse matrix cracks and delaminations occur in all specimens, for regardless of ply orientation, span-to-depth ratio, or previous exposure of specimens to thermal and mechanical fatigue. A small amount of fiber tensile fracture occurs in the outer 0° ply of specimens with high span-to-depth ratios. Because of the complex failure modes, the flexural test results represent the “apparent” strengths rather than the true flexural or shear strenghts for these cross-ply laminates. Thermal cycling of specimens prior to flexural testing does not reduce the apparent flexural strength or change the mode of failure. However, fewer acoustic events are recorded at all strins during flexural testing of specimens exposed to prior thermal cycling. High temperature thermal cycling (32-260°C, 100 cycles) causes a greater reduction in acoustic events than low temperature thermal cycling (-85 to 85°C, 500 cycles). Mechanical cycling (0-50% of the flexural strength, 100 cycles) has a similar effect, except that acoustic events are reduced only at strains less than the maximum strain applied during flexural fatigue. © 1994 John Wiley & Sons, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
    Additional Material: 13 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electroanalysis 4 (1992), S. 439-445 
    ISSN: 1040-0397
    Keywords: Alcohols ; photoelectrochemistry ; amperometric detection ; food ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method for photoelectrochemical detection of alcohols in liquid chromatography and flow injection analysis based on the reaction of the analyte with a photosensitized quinone (benzoquinone) has been developed. Irradiation of the flowing solution and electrochemical detection of the generated photoproduct is carried out within the detector flow cell. Pulsed amperometric detection produced higher sensitivities than conventional potentiostatic amperometry. Samples of vodka and beer were successfully analyzed using the proposed method.
    Additional Material: 6 Ill.
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