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  • Polymer and Materials Science  (105)
  • pH  (2)
  • Wiley-Blackwell  (107)
  • 1
    Electronic Resource
    Electronic Resource
    Ultrasonic degradation of sol rubber in solution (1964)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 8 (1964), S. 2653-2659 
    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: Sol rubber dissolved in three solvents - cyclohexane, petroleum ether (40-60°C. fraction), and toluene - was degraded by ultrasonic waves, the degradation kinetics being followed by measuring spectrophotometrically the consumption of the free radical scavenger α,α′-diphenyl-β-picryl hydrazyl. The kinetic data have been examined by the rate equations developed from two different approaches: one by Jellinek and the other by Ovenall. It has been observed that the number of bonds broken as a function of time can be fitted equally well by both equations in the initial stage, but as the time of degradation increases, especially when the number-average degree of polymerization attains a value less than 3Pe/2, the rate can be described better by Jellinek's equation than that of Ovenall. The rate constants K and the final degree of polymerization for rubber are found to depend on the nature of the solvent.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1964.070080613
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrasonic degradation of macromolecules in solution. Study of degradation kinetics by estimation of free-radical scavenger DPPH and solution viscosity measurementsProd. No. 1357 (1966)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 10 (1966), S. 1089-1098 
    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: The kinetics of degradation of butyl rubber in two solvents, cyclohexane and toluene, was studied by two independent techniques: viscosity measurements and free-radical estimation as a function of DPPH consumed. The general shape of the rate curves in the two cases is similar, but not identical. The rate given by estimation of DPPH is faster than that obtained from solution viscosity data. This has been attributed to the inherent limitations of the two methods for the quantitative determination of the number of breaks occurring in the polymer molecules. The rate is also reduced as the viscosity of the solution medium is increased, which may be correlated with the reduction of the cavitation effect responsible for degradation. The degradation rates in two solvent media initially having the same viscosity were unequal. This may be due to different solvent-solute characteristics, which means that the viscosity and cavitation change to different extents in the two cases throughout the course of degradation. The limiting degree of Polymerization (DP)∞ obtained after prolonged irradiation has been found to be dependent on parameters such as intensity of irradiation, solution viscosity, and initial DP of the molecules.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1966.070100801
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  • 3
    Electronic Resource
    Electronic Resource
    A modeling study of anaerobic biofilm systems: I. Detailed biofilm modeling (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 46 (1995), S. 43-53 
    Details
    ISSN: 0006-3592
    Keywords: acetate ; anaerobic biofilms ; mass transfer ; pH ; biofilm modeling ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A detailed model acetate-utilizing methanogenic biofilms accounting for the diffusion of neutral and ionic species, chemical equilibrium, electroneutrality, gas production within the biofilm, pH-dependent Monod kinetics, and the presence of a concentration boundary layer is presented. The model qualitatively fits the pH profiles that are reported for acetate-utilizing methanogenic aggregates. A sensitivity analysis on the biological parameters showed that the flux of acetate is sensitive to the maximum utilization rate, half-saturation constant, and biofilm density for the bulk conditions investigated. Criteria when traditional biofilm models can be used to predict the flux of acetate into the biofilm are established. If the maximum pH change predicted using a hypothetical system is within ±0.05, the traditional model predicts the flux to within ±5% of the value calculated with the model developed in this study. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260460107
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  • 4
    Electronic Resource
    Electronic Resource
    Viscometric determination of molecular weight of cellulose pulps in zinc ethylenediamine solutionCommunication No. 473 from the National Chemical Laboratory, Poona-8, India. (1963)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 7 (1963), S. 181-186 
    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 convenient method of preparing zinc ethylenediamine complex (ZED) solution for use as solvent for cellulose pulp is described, and the advantages in using this solvent (0.25M zinc in 41% ethylenediamine in water) over cupriethylenediamine (CED) or cuprammonium solutions for viscometric determination of molecular weight of cellulose are indicated. Intrinsic viscosities of eight rayon-grade pulp solutions have been determined at four temperatures: 15, 20, 25, and 30°C. The constants K = 5.85 × 10-5 and a = 0.936 of the Mark-Houwink equation [η] = KMna, required for evaluating the molecular weight of cellulose pulps in ZED solution, have been determined by using the molecular weight values obtained from CED solutions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1963.070070116
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  • 5
    Electronic Resource
    Electronic Resource
    A modeling study of anaerobic biofilm systems: II. Reactor modeling (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 46 (1995), S. 54-61 
    Details
    ISSN: 0006-3592
    Keywords: anaerobic biofilm ; CSTR ; reactors, nonide ; pH ; plug-flow reactors ; biofilm modeling ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A rigorous steady-state model of anaerobic biofilm reactors taking into account acid-base and gas-phase equilibria in the reactor in conjunction with detailed chemical equilibria and mass transfer in acetate-utilizing methanogenic biofilms is presented. The performances of ideal completely stirred tank reactors (CSTRs) and plug-flow reactors, as well as reactors with nonideal hydraulic conditions, are simulated. Decreasing the surface loading rate increases the acetate removal efficiency, while decreasing the influent pH and increasing the buffering capacity improves the removal efficiency only if the bulk pH of the reactor shifts toward more optimal values between 6.8 to 7.0. The reactor can have negative or positive removal efficiencies depending on the start-up conditions. The respiration coefficient plays a critical role in determining the minimum influent pH required for reactor recovery after failure. Having multiple CSTRs-in-series generally increases the overall removal efficiency for the influent conditions investigated. Monitoring of the influent feed quality is critical for plug-flow reactors, becasue failure of the initial sections of the reactor may cause a cascading effect that may lead to a rapid reactor failure. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260460108
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  • 6
    Electronic Resource
    Electronic Resource
    A study on the thermal degradation of rubber in dilute solutionsCommunication No. 529 from the National Chemical Laboratory, Poona-8, India. (1963)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 7 (1963), S. 2199-2209 
    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: The kinetics of low-temperature (60-100°C.) thermal degradation of deproteinized and deresinified petroleum ether soluble fraction of natural rubber in two chemically inert solvents, cyclohexane and trans-decalin, have been studied. The changes in Mw, A2, and (r2)1/2 at various stages of degradation have been obtained from the lightscattering data. The rate constants and the energy of activation for chain scission have been calculated from the observed variation in Mu. The scission has been found to be random and the average energy of activation is 25.8 kcal./mole. This low-energy requirement suggests the presence of weak links in the rubber molecule which get ruptured at low temperature.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1963.070070619
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  • 7
    Electronic Resource
    Electronic Resource
    A cation exchange resin from poly(N-vinyl carbazole) (1978)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 72 (1978), S. 57-66 
    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: Poly(N-vinylcarbazol) wurde mit verschiedenen Reagenzien sulfoniert und die Ionenaustauschkapazität der erhaltenen Harze bestimmt. Eine maximale Kapazität von 4,5 meq · g-1 des trockenen Harzes wurde durch 10stündige Reaktion mit 98,8proz. H2SO4 bei 30°C erhalten. Die pH-Titrationskurven lassen einen starken monofunktionellen Kationenaustauscher mit einem pK-Wert von 2,2 erkennen. Das Harz zeigt eine mäßige Austauschgeschwindigkeit mit NaCl und ist bis zu 250°C thermisch stabil.
    Notes: Poly(N-vinyl carbazole) was sulfonated with different sulfonating agents and ion exchange capacities of the resins produced were evaluated. A maximum capacity of 4.5 meq · g-1 of dry resin was realized when sulfonation was done with 98.8% H2SO4 at 30°C for 10 h. The pH titration curves reveal the nature of a strong monofunctional cation exchanger with a pK value of 2.2. The resin exhibits a moderate rate of exchange with NaCl and is thermally stable up to ca. 250°C.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1978.050720105
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  • 8
    Electronic Resource
    Electronic Resource
    A cation exchange resin based on the condensation product of poly(iso-butyl vinyl ether) and furfural (1978)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 73 (1978), S. 53-61 
    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: Ein Kationenaustauscher wurde durch Kondensation von Polyisobutylvinyläther und Furfural hergestellt. Als Katalysator diente konzentrierte Schwefelsäure. Der Austauscher wurde durch Messen der Austauschkapazität, durch Untersuchen seiner thermischen Belastbarkeit und durch Bestimmen seines Verhaltens bei der pH-Titration charakterisiert. Es scheint sich um einen Austauscher mit schwachen Säregruppen zu handlen, die wohl als —COOH-Gruppen vorliegen und durch Oxidation aus den Furfuralgruppen entstanden sein dürften.
    Notes: A cation exchange resin was synthesized from the condensation product of poly(iso-butyl vinyl ether) and furfural by treating it with concentration sulphuric acid. The resin produced was characterized by measuring its total and salt splitting capacities, and by studying its thermal characteristics and behaviour to pH metric titration. The latter suggests the resin to be a weak one possibly containing —COOH groups, which result from the oxidation of the furfural aldehyde group by sulphuric acid.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1978.050730104
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  • 9
    Electronic Resource
    Electronic Resource
    Studies on carbazole based polyarylates (1981)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 97 (1981), S. 79-90 
    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: Es wurde ein neues Polyarylat aus Carbazol und Resorcinol nach der Methode der Lösungskondensation bei niedriger Temperatur unter Verwendung von Pyridin als Katalysator hergestellt. Das Polymere wurde im Hinblick auf seine Struktur, thermische Stabilität und sein dielektrisches Verhalten charakterisiert. Der Einfluß des Diphenolenteils auf die thermischen und dielektrischen Eigenschaften dieses Polyarylats und anderer auf Carbazolbasis wurde untersucht.
    Notes: A novel polyarylate has been synthesized from carbazole and resorcinol by low temperature solution condensation method using as an acceptor-catalytic reagent pyridine. It has been characterized in respect of its structure, thermal stability and dielectric behaviour. The influence of the diphenol moiety on the thermal and the dielectric properties of this polyarylate and the others based on carbazole has been studied.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1981.050970107
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  • 10
    Electronic Resource
    Electronic Resource
    Vinyl polymerization by carbon black, IV. Some properties of modified carbon black compared with its polymerization initiating activity (1985)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 129 (1985), S. 43-59 
    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: Alle Arten von Ruß enthalten große Anteile an ungepaarten Elektronen und organischen funktionellen Gruppen. Die Polymerisation wird wahrscheinlich durch die ungepaarten Elektronen auf der Oberfläche ausgelöst; die funktionellen Gruppen haben auf die auslösende Reaktion einen Promotor-Effekt. Alle Eigenschaften wie Textur, Geometrie, Größe der Oberfläche, pH der wäßrigen Aufschlämmung, Aschegehalt und elementare Zusammensetzung haben Einfluß auf die Polymerisation. Diese einschlägigen physikochemischen und Oberflächen-Eigenschaften von nicht modifiziertem und modifiziertem Ruß N 220 wurden im Hinblick auf die Polymerisation von N-Vinylcarbazol untersucht.
    Notes: All grades of carbon black contain large amounts of unpaired electrons and organic functional groups. Polymerization reaction is possibly initiated by the unpaired electrons on the surface; the functional groups have promotional effect on the initiation process. All the properties like texture, geometry, surface area, pH of the aqueous slurry, ash content, and elemental composition have effects on the polymerization reaction. These pertinent physicochemical and surface properties of unmodified and modified N 220 carbon black have been studied in relation to N-vinylcarbazole polymerization.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1985.051290104
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