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  • 2000-2004
  • 1990-1994  (46)
  • 1975-1979  (27)
  • Polymer and Materials Science  (73)
  • 1
    Electronic Resource
    Electronic Resource
    Thermodynamic cycle-perturbation study of the binding of trifluoroacetyl dipeptide anilide inhibitors with porcine pancreatic elastase (1990)
    New York : Wiley-Blackwell
    Biopolymers 30 (1990), S. 773-780 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The variety of results of crystallographic studies of the serine proteases complexed with isocoumnrin inhibitors presents a challenging problem to modeling methods and molecular energetics. Therefore, the thermodynamic cycle-perturbation technique has been used to study a model system of elastase and two peptidic inhibitors. Using the program AMBER, the technique correctly predicts changes of the binding constants for the trifluoroacetyl dipeptide inhibitors in comparison with available experimental (kinetic and crystallographic) data. However, the absolute values obtained are shown to be sensitive to the specific electrostatic interaction potential parameters used in the simulations. The reader and user are cautioned that thermodynamic cyle-perturbation results may be too optimistic by underestimating the accuracy of free energy values. This is especially a matter of concern for those cases where a direct comparison with experimental values is not possible, viz., (1) the simulation of binding of novel compounds, (2) structurally uncertain binding sites, or (3) structurally different binding modes. With our best 4-31G* ESP (electrostatic potential) charges we were able to reproduce experimentally determined free energy differences (ΔΔA) with an accuracy of about 1.5 kcal/mol. Dynamically induced structural changes in the binding site of elastase, and particularly changes in hydrogen-bond patterns of the binding site, are also reported.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360300712
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  • 2
    Electronic Resource
    Electronic Resource
    Correlation between microscopic structural parameters and macroscopic flow behaviour of some polymer-surfactant systems suitable for tertiary oil recovery (1992)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 195 (1992), S. 57-77 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Einige für den kombinierten Polymer-Tensid-Einsatz in der tertiären Erdölförderung (EOR) diskutierte Substanzen wurden mittels statischer und dynamischer Lichtstreuung charakterisiert und bezüglich ihrer Anwendbarkeit in unterschiedlich salinaren Modellwässern durch rheologische und rheologisch-dynamische Messungen unter-sucht.Als Polymere wurden Xanthan sowie unterschiedlich hydrolysierte Polyacrylamide verwendet, als Tensid ein Ethylenglykolsulfonat. Es ließen sich Korrelationen zwischen mikroskopischen Strukturparametern (z. B. hydrodynamischer Radius, Trägheitsradius, Molekulargewicht, Gestaltparameter der gelösten Polymeren) und makroskopischem Verhalten wie Viskosität aufstellen, welche für den EOR-Einsatz wichtige rheologische Parameter darstellen.Mit ergänzenden Messungen (Oberflächenspannung, zeitabhängiges Viskositätsverhalten) können Aussagen über die Effizienz und Langzeitstabilität eingesetzter Polymer-Tensid-Slugs in unterschiedlich salinaren Lagerstätten gemacht werden.
    Notes: Some materials, suitable for application in polymer-surfactant flooding used in tertiary oil recovery (EOR), have been characterized by static and dynamic light scattering and studied in respect to their suitability in various model brines by measuring their rheological and dynamic-rheological behaviour. Xanthan and polyacrylamides of different degree of hydrolysis have been used as polymers, an ethylene glycol sulfonate as surfactant.Correlations have been established between microscopic structural parameters (Hydrodynamic radius, radius of gyration, molar mass, shape of the polymers) and the macroscopic behaviour, such as viscosity and elasticity, being important rheological parameters for EOR application. Additional investigations on surface tension and long term viscosity study lead then to a judgement for the efficiency and long term stability of polymer-surfactant slugs in various reservoirs of different salinity.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1992.051950104
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  • 3
    Electronic Resource
    Electronic Resource
    A method for measuring sedimentation and diffusion of macromolecules in capillary tubes by total intensity and quasi-elastic light-scattering techniquesPresented in part at the Symposium on New Generation Instrumentation in Rheology, Rheology Society, Cincinnati, Ohio, January 1973, by M. H. Birnboim. (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 419-430 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Light scattered from a macromolecular solution in a capillary tube is used to determine both the sedimentation and translational diffusion coefficients. The capillary tube is spun in a preparative centrifuge, removed, and placed in a light-scattering photometer equipped with a scanning mechanism. The intensity distribution of scattered light along the tube represents the concentration profile in the tube and provides the measure of boundary migration. The sedimentation coefficient is determined from this measure and the applied centrifugal field. The diffusion coefficient is obtained from a time-autocorrelation analysis of fluctuations in intensity of light scattered from any fixed point of the profile. These coefficients were obtained for two monodisperse systems, R17 bacteriophage and 28s ribosomal rat liver RNA. The molecular weights obtained from ratios of these coefficients are in good agreement with literature values. In the sedimentation analysis, deviations from linearity between boundary displacement and applied field were found to be less than 1%. This precision confirms that the boundary is stable for the capillary geometry even in the absence of a preformed density gradient. The sedimentation coefficients of identical samples were also measured with the Spinco Model E analytical ultracentrifuge; results of the two methods agree to within 4%.As a consequence of the capillary tube geometry and light-scattering detection, sedimentation coefficients can be obtained from sample volumes of less than 100 μl. This detection techniques is thus far demonstrated to be at least an order of magnitude more sensitive than Schlieren optics, thereby useful when uv absorption is not applicable. For diffusion measurements there are also several inherent advantages. The diffusion coefficient is obtained from the identical sample, and scanning provides the capability to measure D from various parts of the sedimentation profiles and thereby directly explore concentration dependence, homogeneity, and integrity of the sample. The capillary tube with a layer of silicone oil over the sample and centrifugation provides an effective method to cleanse the solution and trap all dust.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140214
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  • 4
    Electronic Resource
    Electronic Resource
    A contribution to the mechanism of the “four-center-type” photopolymerization (1977)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 631-634 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1977.021780233
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  • 5
    Electronic Resource
    Electronic Resource
    Copolymers of ethyl p-vinylbenzenesulfonate for the preparation of polyelectrolytes of reproducible ion content (1993)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 194 (1993), S. 1237-1248 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Ethyl p-vinylbenzenesulfonate (ESS) for which a new synthesis is described has been copolymerized with vinylcarbazole, styrene, p-methylstyrene and p-bromostyrene in N,N-dimethylformamide at 60°C using azoisobutyronitrile as initiator. Copolymer compositions and copolymerization parameters have been evaluated. Q, e-values for ESS are 4,19 and -0,11. Thermal properties of the copolymers have been investigated by differential scanning calorimetry and thermogravimetric analysis. Polyelectrolytes have been prepared either by polymer analogous hydrolysis of the sulfonic acid esters followed by conversion of the free acids into alkali metal salts or by using the alkylating properties of the esters towards tertiary amines or pyridines to form the appropriate sulfonic acid ammonium or pyridinium salts. The latter method offers the opportunity to synthesize polyelectrolytes with a well defined content of chromophores.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1993.021940417
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  • 6
    Electronic Resource
    Electronic Resource
    Polymere mit dem Zentralatom eines makrocyclus in der hauptkette, 2.1. Mitteilung: cf.1. Polykondensationsreaktionen mit Germaniumkomplexen des Phthalocyanins und meso-Tetraphenylporphins (1975)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 176 (1975), S. 831-847 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Dihydroxy(phthalocyanino)germanium (1b) and Dihydroxy(tetraphenylporphino)germanium (3b) react with different monovalent alcohols to afford low-molecular bisalkoxyderivatives (1c-f and 3c-h). With bivalent alcohols and phenols polymers of the structure 5 and 6 or 8a, 9a and 8b, 9b, resp., are obtained.Dichloro(phthalocyanino)germanium (1a) and Dichlor(tetraphenylporphino)germanium (3a) react also with phenol, resp. hydroquinone, to give low-molecular and polymeric phenoxy-derivatives. The reaction of 1b and 3b with mono- and dibasic carboxylic acids leads to the corresponding esters.Dehydration of 3b gives polymeric porphin 15.The IR-spectra of the prepared compounds are discussed and compared with the analogous complexes of hemiporphyrazingermanium.Thermogravimetric and semiconductive measurements (σ298K = 10-10 - 10-15Ω-1 cm-1) are described.
    Notes: Dihydroxyphthalocyaningermanium (1b) und Dihydroxytetraphenylporphingermanium (3b) werden mit verschiedenen einwertigen Alkoholen zu den niedermolekularen Bisalkoxy-Derivaten (1c-f bzw. 3c-h) umgesetzt. Mit zweiwertigen Alkoholen und Phenolen können Polymere der Struktur 5 und 6 bzw. 8a, 9a und 8b, 9b erhalten werden.Dichlorphthalocyaningermanium (1a) und Dichlortetraphenylporphingermanium (3a) reagieren mit Phenol bzw. Hydrochinon ebenfalls zu niedermolekularen und polymeren Phenoxy-Derivaten. Die Umsetzung von 1b und 3b mit ein- und zweibasischen Carbonsäuren führt zu den entsprechenden Estern.Durch Dehydratisierung von 3b kann das polymere Porphin 15 hergestellt werden.Die IR-Spektren der dargestellten Verbindungen werden im Vergleich zu den analogen Hemiporphyrazingermaniumkomplexen diskutiert. Thermogravimetrische und Halbleitermessungen (σ298 K = 10-10 - 10-15Ω-1 cm-1) werden beschrieben.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1975.021760401
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  • 7
    Electronic Resource
    Electronic Resource
    Polymere mit dem zentralatom eines makrocyclus in der hauptkette, 3.2. Mitteilung: cf.2.Polykondensationsreaktionen mit zinnkomplexen des meso-tetraphenylporphins, phthalocyanins und hemiporphyrazins (1975)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 176 (1975), S. 1919-1927 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Dihydroxy(meso-tetraphenylporphino)tin (1b), dihydroxy(phthalocyanino)tin (1d), and dihydroxy(hemiporphyrazino)tin (1f) react with bivalent phenols to afford polymers of type B. With 1,2-ethanediol and 1b low molecular compound 3 is obtained, which eliminates 1,2-ethanediol to give poly[oxyethyleneoxy(meso-tetraphenylporphin)stannandiyl] (4). Dehydration of the dihydroxy compounds 1b, 1d, 1f leads to polymers of type C. The IR-spectra of the prepared compounds are discussed; thermogravimetric and semiconductive measurements (σ298K≈10-6-10-16Ω-1cm-1) are described and compared with the analogous complexes of germanium.
    Notes: Dihydroxy-meso-tetraphenylporphinzinn (1b), Dihydroxyphthalocyaninzinn (1d) und Dihydroxyhemiporphyrazinzinn (1f) reagieren mit zweiwertigen Phenolen zu Polymeren des Typs B. Aus Äthylenglykol und 1b läßt sich die niedermolekulare Verbindung 3 erhalten, die unter Äthylenglykolabspaltung Poly[oxyäthylenoxy(meso-tetraphenylporphin)stannandiyl] (4) ergibt.Durch Dehydratation der Dihydroxy-Verbindungen 1b, 1d, 1f lassen sich Polymere des Typs C synthetisieren.Die IR-Spektren der dargestellten Verbindungen werden diskutiert; thermogravimetrische und Halbleitermessungen (σ298K≈10-6-10-16Ω-1cm-1) werden beschrieben und mit den analogen Germaniumverbindungen verglichen.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1975.021760702
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  • 8
    Electronic Resource
    Electronic Resource
    Polymers with pendant carbazolyl groups, 5Part 4: cf.3.. Photoconductive properties of some carbazole derivatives with electron donor and acceptor groups (1991)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 192 (1991), S. 617-629 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In this paper photocurrents of N-isopropylcarbazole (NIPC) derivatives in polycarbonate hosts are reported and compared to data for a benzotriazole derivative (BTA). The carbazole moiety was substituted with both electron donor and acceptor substituents and the photoconductivity was measured as a function of concentration, electrical field, and temperature using the time-of-flight (TOF) technique. The observed increase of the effective mobility of charge carriers at low dopant concentrations upon substitution with a moderate electron acceptor is in contrast to literature data for some other materials. We interpret this increase as being due to an increase in the delocalisation radius of the transport state of the substituted carbazole molecule. The field dependence of the effective mobility shows Poole-Frenkel behaviour, which is attributed to polaron formation. Comparison of the effective mobility of the NIPC derivatives with BTA shows that the size of the molecule plays a decisive role for the absolute value of the effective mobility.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1991.021920313
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  • 9
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of dextran radiocontrast carriers, 1. Ether methylamide derivatives (1991)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 192 (1991), S. 2603-2613 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The synthesis of dextran radiocontrast carriers was undertaken to obtain derivatives expected to have slow and controlled biodegradation as well as slow extravascular diffusion features. The results presented here particularly concern derivatives including a methylamide spacer, prepared by condensation of the amine function of the contrast product with carboxymethylated dextran (CMD). The effect of various coupling reagents on the final yields is disucssed. Concerning the macromolecular features, all the synthesized products were characterized by acid-base titration, elemental analysis, flame photometry, spectroscopic determinations and gel-permeation chromatography. GPC showed that the carboxymethylation of dextran leads to some reticulation (doubling the molecular weights), whereas the coupling of CMD with the contrast compound does not alter the molecular weight and the polydispersity index of the products appreciably.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1991.021921107
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  • 10
    Electronic Resource
    Electronic Resource
    Compatibility of ABA poly(styrene-b-isoprene)/poly(2,6-dimethylphenylene oxide) blends (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 719-725 
    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 variety of blends of ABA poly(styrene-b-isoprene) copolymers with poly(2,6-dimethylphenylene oxide) were prepared. Their compatibility was examined by measuring both the apparent modulus of rigidity and the loss tangent. Several blends showed a unique glass transition temperature between those of the individual components, which indicated compatibility. It was found that only those copolymers which phase separate are compatible with poly(2,6-dimethylphenylene oxide).
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1978.070220312
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