ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (20)
  • kinetics
  • 1985-1989  (20)
  • Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics  (20)
  • Energy, Environment Protection, Nuclear Power Engineering
Collection
  • Articles  (20)
Source
Keywords
Publisher
Years
Year
Topic
  • 1
    Electronic Resource
    Electronic Resource
    On the theory of photoadsorption kinetics of a-Se colloids: The thermal activation energy and compensation effect (1988)
    Springer
    Colloid & polymer science 266 (1988), S. 958-964 
    Details
    ISSN: 1435-1536
    Keywords: a-Se colloids ; photoadsorption ; kinetics ; activation energy ; compensation effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In this study, a model is developed to explain in microscopic terms the results obtained from thermally activated photoadsorption experiments in a-Se colloids. The observed compensation effect can be described for two different cases. At low efficiency adsorption, the process is controlled by the potential at the boundary layer. In the high efficiency adsorption case, the process is controlled by diffusion transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410853
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Laser temperature jump experiments with fluorescence polarization and turbidity detection on the phase transition of single shell vesicles of dimyristoylphosphatidylcholine (1985)
    Springer
    Colloid & polymer science 263 (1985), S. 484-493 
    Details
    ISSN: 1435-1536
    Keywords: Phospholipid bilayer ; kinetics ; laser temperature jump ; phase transition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The iodine-laser temperature-jump technique has been used to investigate the main phase transition in single shell vesicles of dimyristoylphosphatidylcholine. The probe molecules DPH and TMA-DPH were incorporated into the lipid bilayer and laserT-jump experiments with turbidity and flourescence polarization detection were performed. We found three well separated relaxation processes between 5 μs and 10 ms. The relaxation signals showed strong cooperativity in the relaxation times as well as in their corresponding amplituedes. We attributed the relaxation to the formation and dissolution of clusters of different order inside the bilayer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01458339
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Radical desorption in the emulsion polymerisation of vinyl monomers (1987)
    Springer
    Colloid & polymer science 265 (1987), S. 58-64 
    Details
    ISSN: 1435-1536
    Keywords: Polymerisation ; emulsion ; styrene ; methylmethacrylate ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The dependence of emulsion polymerisation rates on a number of important parameters is considered. Attention is paid to the use of seeded emulsion systems for the evaluation of radical desorption coefficients (k o). Experimental conditions are shown to be important. When the average number of radicals per particle is low, large changes in the rate coefficient for chain termination do not have a large effect on the kinetics. With styrene and methylmethacrylate, radical re-absorption by the polymer particles is shown to be important and radical capture efficiences can be high. Consistency is established between the results of a number of workers and values fork o are shown to be lower than those calculated from chain transfer rates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01422665
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Plasma-chemical reactions in weakly decomposed CCl4 (1985)
    Springer
    Plasma chemistry and plasma processing 5 (1985), S. 293-316 
    Details
    ISSN: 1572-8986
    Keywords: Plasma chemistry ; halocarbon decomposition ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract For the case of weak feed gas decomposition, where the concentration of CCl4 exceeds those of decomposition and built-up products, the emission of CCl* is shown to originate from dissociative excitation of CCl4. With electron concentration measured independently, the kinetics of CCl4 decomposition has been extracted from the time dependence of the CCl* intensity. Supported by EPR determinations of radical concentrations in rapidly flowing CCl4 and CCl4/O2 afterglows, the primary decomposition reaction is shown to be the electron impact dissociation into CCl3 and Cl. Its rate constant (k 1=4×10−8 cm3s−1) indicates strongly that dissociative electron attachment is the main reaction channel at least at r.f. power densities just above the threshold of a self-maintaining discharge. At extremely low mean electron energies the emission of a continuum is observed, which is tentatively ascribed to the radiative CCl3-Cl recombination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00566006
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Dynamics of the formation and decay of C2(a 3II u ,v″=0) radical in a pulse discharge in methane (1986)
    Springer
    Plasma chemistry and plasma processing 6 (1986), S. 429-436 
    Details
    ISSN: 1572-8986
    Keywords: Plasma ; laser ; diagnostics ; free radicals ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The plasma of a pulse discharge (0.05 J/cm3) in methane at low pressure (200 Pa) is studied. The dynamics of formation and decay of C2(a3IIu, v″=0) is monitored using a stroboscopic laser absorption method. It was found that substantial amounts of C2, 1015 cm−3, arise with a 1-µs delay after the current pulse.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00565554
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Dynamics of the formation of excited hydrogen, H(n=2,3,4), during a pulse discharge in methane (1988)
    Springer
    Plasma chemistry and plasma processing 8 (1988), S. 101-110 
    Details
    ISSN: 1572-8986
    Keywords: Plasma ; laser ; diagnostics ; hydrocarbons ; free radicals ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The dynamics of the formation and decay of excited hydrogen during a pulse discharge in methane at a pressure of 200 Pa and energy density of 0.05 J/cm3 has been studied. The population of hydrogen in the n=2 state was monitored by the laser absorption method. The time constant of the decay of the excited hydrogen was measured to be 95±15 ns. The concentration of free electrons reached a maximum value of 7×1014 cm−3, and the time constant of their recombination was 220±50 ns. The formation of appreciable amounts of atomic hydrogen in the ground state during the discharge, H(n=1)〉1016 cm−3, was estimated on the basis of a kinetic model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01016934
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Plasma-chemical methane conversion under nonthermal and thermal conditions: An attempt toward uniform kinetic modeling (1985)
    Springer
    Plasma chemistry and plasma processing 5 (1985), S. 283-291 
    Details
    ISSN: 1572-8986
    Keywords: Methane ; acetylene ; kinetics ; modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract It is shown that it is basically possible to model plasma-chemical methane conversion using a kinetic concept regardless of the kind of plasma, i.e., the kind of activation. While the temporal plasma-chemical decomposition of methane is controlled by a first-order rate equation, the temporal product formation can be described by a set of first-order consecutive reactions. Prolonged portions of constant product concentrations in the temporal product formation curves were explained by the assumption of an equilibrium between forward and reverse reactions. The modeling revealed the special role of the re-formation of dissociated molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00615127
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    The oxidation of cobalt-chromium-titanium alloys at 1000°C (1986)
    Springer
    Oxidation of metals 26 (1986), S. 139-155 
    Details
    ISSN: 1573-4889
    Keywords: oxidation ; Co-Cr-Ti alloys ; kinetics ; scale morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Cobalt-based alloys containing 3,5,10,15, and 20% Cr with 1 and 3% Ti were oxidized at 1000°C in slowly flowing oxygen gas. In general, titanium additions decreased the oxidation rate with the most pronounced effect being observed at the 10% Cr level. Titanium accelerated the formation of Cr2O3 layers at the metal-oxide interface. Faceted CrxTiyOz spinel particles were found at the metal-oxide interface which varied in composition according to microprobe results. There was no evidence of spalling on the Co-Cr-Ti alloys studied in contrast to the severe spalling normally encountered in Ni-Cr-Ti alloys. Distinct morphological differences existed on the outer CoO layer of the 1% Ti alloys in comparison to the O and 3% Ti alloys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00664278
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Effect of scale constitution on the carburization of heat resistant steels (1986)
    Springer
    Oxidation of metals 26 (1986), S. 417-430 
    Details
    ISSN: 1573-4889
    Keywords: cyclic carburization-oxidation ; carbides ; austenite ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Several austenitic heat-resistant steels were exposed to alternating periods of carburization at 1273 K [a c= 1,po2〈10−28 atm] and oxidation at 973°K [a c≈ O,po2 = 0.2 atm]. In all cases the depth of internal carbide precipitation increased with cumulative carburization time. It was found that the carburization rates of high nickel content alloys were unaffected by intermittent oxidation cycles, whereas the low nickel, high iron content alloys experienced a reduction in carburization rate subsequent to oxidation treatment. The latter group of alloys formed external scales of chromium-rich M7C3 which were shown by sulfur tracing experiments to be gas permeable. It was concluded, therefore, that oxidation of these materials led to blockage of cracks and holes in the scales, thereby decreasing the surface carbon activity and hence the carburization rate. High nickel, low iron alloys formed external scales of chromium-rich M7C3 covered by Cr3C2. These scales were shown to have very low gas permeabilities. It was concluded that the carbon activity at the surface of these alloys was controlled by scale-alloy equilibration, and was therefore not affected by brief periods of oxidation. The pattern of carbide scale formation is qualitatively consistent with the thermodynamics of the Fe-Cr-C system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00659345
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Effect of yttrium on the sulfidation behavior of Ni-Cr-Al alloys at 700°C (1986)
    Springer
    Oxidation of metals 25 (1986), S. 1-28 
    Details
    ISSN: 1573-4889
    Keywords: sulfidation ; yttrium ; duplex-sulfide scales ; lamellar sulfides ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The sulfidation of Ni-10Cr-5Al, Ni-20Cr-5Al, and Ni-50Cr-5Al, and of the same alloys containing 1% Y, was studied in 0.1 atm sulfur vapor at 700°C. The sulfidation process followed linear kinetics for all the alloys except Ni-50Cr-5Al-1Y, and possibly Ni-50Cr-5Al, which followed the parabolic law. The reaction rates decreased with increasing chromium content in alloys without yttrium, and the addition of yttrium reduced the rates by at least a factor of two for the alloys containing 10 and 20% Cr and by an order of magnitude for Ni-50Cr-5Al. Alloys containing 10 and 20% Cr (with and without yttrium) formed duplex scales consisting of an outer layer of NiS1.03 and an inner lamellar layer of a very fine mixture of Cr2S3 and A12O3 in a matrix of NiS1.03. The two alloys containing 50% Cr formed only a compact layer of Cr2S3, which was brittle and spalled during cooling. The lamellae in the duplex scales were parallel to the specimen surface and bent around corners. The lamellae were thicker than those on Ni-Al binary alloys. The lamellae were also thicker in scales on the 20% Cr alloy than on the 10% Cr alloy. The presence of yttrium refined the lamellae and increased the lamellae density near the scale/metal interface in the 10% alloy, but in the 20% Cr alloy the lammellae were thicker and more closely spaced. Platinum markers were found in the inner portion of the exterior NiS1.03 layer close to the lamellar zone. A counter-current diffusion mechanism is proposed involving outward cation diffusion and inward sulfur diffusion, although diffusion was not rate controlling for alloys containing 10 and 20% Cr. Auger analysis of scales formed on Ni-50Cr-1Y showed an even distribution of yttrium throughout the layer of Cr2S3, suggesting that some yttrium dissolved in the sulfide. The reduced sulfidation rate of samples containing yttrium is explained by the possible dissolution of yttrium as a donor. The presence of Y4+ would then decrease the concentration of interstitial chromium ions in the N-type layer of Cr2S3, which would decrease the reaction rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807994
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Formation and growth of spinel and Cr2O3 oxides on 20% Cr-25% Ni-Nb stainless steel in CO2 environments (1985)
    Springer
    Oxidation of metals 23 (1985), S. 207-235 
    Details
    ISSN: 1573-4889
    Keywords: stainless steel ; duplex oxide ; kinetics ; growth rates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The nature of the first-formed oxide on 20% Cr/25% Ni/Nb stabilized steel during exposure to CO2 at high and low temperatures has been determined by surface analytical techniques. These results together with a consideration of gas/solid interactions show that the oxide produced may be determined by kinetics or thermodynamic factors, and a diagram is presented to show that rhombohedral Cr2O3 or spinel may be the oxide first formed. Under most standard conditions, a mixed spinel oxide is formed initially, and the subsequent growth of a duplex oxide is analyzed in terms of a solid-state reaction in which the spinel oxide is reduced to Cr2O3 at the metal/oxide interface. Diffusion control of growth by either spinel or Cr2O3 is incorporated in new equations describing the kinetics of oxidation, and weight-gain predictions are tested against experimental observations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00659904
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Molten carbonate-induced hot corrosion of nickel (1989)
    Springer
    Oxidation of metals 32 (1989), S. 225-240 
    Details
    ISSN: 1573-4889
    Keywords: Hot corrosion ; nickel ; TGA ; kinetics ; mechanism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The accelerated oxidation of pure nickel in the presence of a molten carbonate mixture has been studied in O2 and CO2-containing atmospheres. The oxidation rate of nickel with carbonate coatings was at least four orders of magnitude faster than that without salt coatings. The extent of oxidation, in terms of unit area weight gain, depended on both the amount of carbonate mixture coatings and the gas atmosphere. The unit area weight gain due to oxidation increased with increasing amounts of salt coatings up to a certain value. These observations suggest that the termination of nickel oxidation results from the exhaustion of either the salt coatings or metallic nickel. Porous and particulate oxide products were observed from scanning electron microscopic (SEM) examinations. The energy-dispersive analysis of x-rays (EDAX) shows that no salt remains on the specimen surface after the oxidation experiment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00664800
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Kinetics of oxidation of ferrous alloys by super-heated steam (1987)
    Springer
    Oxidation of metals 28 (1987), S. 237-258 
    Details
    ISSN: 1573-4889
    Keywords: Steel oxidation ; duplex scale ; steam ; activation energy ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The kinetics of the oxidation of ferrous alloys in steam (10–60 kPa) at 450–550°C have been studied by measuring both the rate of hydrogen emission and the amount of metal oxidized. Excellent agreement has been found between the amount of metal oxidized calculated from both the total mass of hydrogen produced in the reaction and the thickness of the oxide layer formed; rate constants calculated from the rate of hydrogen emission, the mass of hydrogen produced as the reaction proceeds, and the oxide formed agree within experimental error. The rate of oxidation of a 9%Cr-1%Mo alloy at 501°C was found to be independent of the partial pressure of the steam. For this alloy, the activation energy agreed with literature values obtained at higher temperatures and pressures. The effect of the chromium and silicon content on the oxidation rates is compared. The rate constants are compared with theoretical calculations, assuming that the rate is determined by diffusion of iron in the magnetite lattice. For the 9%Cr-1%Mo alloy, the parabolic rate constant and activation energy are in excellent agreement with values calculated using Wagner's theory. The experimental rate constants are greater for the alloys containing smaller amounts of chromium; diffusion of iron along magnetite grain boundaries may be the dominant mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00666721
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Mechanisms of high-temperature corrosion in helium containing small amounts of impurities. II. Corrosion of the nickel-base alloy inconel 617 (1988)
    Springer
    Oxidation of metals 30 (1988), S. 27-51 
    Details
    ISSN: 1573-4889
    Keywords: Ni-base alloy IN 617 ; reactor helium ; oxidation ; carburization ; decarburization ; kinetics ; mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Application of the technical nickel-base alloy IN 617 in the primary circuit of the high-temperature gas-cooled reactor is limited essentially by the chemical reactions with the impurities (CO, CO2, H2, CH4, H2O) in the helium coolant. The interactions of the alloy with the reactive impurities in different helium-base gases were investigated by thermogravimetry in a gas-tight microbalance and by simultaneous measurement of the changes in gas composition by a continuous sensitive mass spectrometric analysis. The results demonstrate that the set of six reaction equations deduced in part 1 can be applied to describe the corrosion of the alloy. The occurrence of the various reactions is determined essentially by temperature. For the case of a standardized helium gas (HHT-He), three temperature regions can be distinguished. Below a critical temperature (about 1105 K), the presence of CO can cause simultaneous oxidation and carburization. Above this temperature, this reaction does not reverse itself. Rather, oxidation by CO2 and H2O takes place that shows, after a transient period, the same kinetics observed in undiluted oxygen-containing gases. At temperatures above about 1205 K, decarburization of the alloy accompanied by the production of CO takes place, leading to severe destruction of the carbide microstructure and, therefore, limiting the applicability of the material.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00656643
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Oxidation of high-aluminum austenitic stainless steels (1988)
    Springer
    Oxidation of metals 30 (1988), S. 185-200 
    Details
    ISSN: 1573-4889
    Keywords: austenitic steels ; oxidation resistance ; protective αA12O3 film ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The cyclical oxidation behavior of an austenitic stainless steel (24% Ni, 10% Cr, 5% Al, and balance Fe) has been evaluated in the temperature range 800–1300°C. The effects of trace elements such as S, Y, Zr, and Ti on the oxidation of the austenitic stainless steel have also been evaluated. The results indicate that Fe-Ni-Cr-Al stainless steels exhibit superior oxidation resistance up to 1300°C due to the formation of a very adherent and thin film of α-Al2O3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00666596
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    In situ SAXS investigations of isothermal crystallization in poly(TMPS) fractions (1987)
    Springer
    Colloid & polymer science 265 (1987), S. 193-205 
    Details
    ISSN: 1435-1536
    Keywords: Poly(TMPS) ; in situ ; SAXS ; crystallization ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The isothermal crystallization kinetics of poly(TMPS) has been measured by ISSAXS and results obtained for a molecular weight fraction (21,000) below the critical entanglement molecular weight (25,000) and another one above it (371,000). The SAXS intensity vs. time curves suggest that a single transformation mechanism exists. The SAXS long period is independent of crystallization time for both poly(TMPS) fractions. However the interlamellar thickness contribution to the long period is dependent upon molecular weight and crystallization temperature, increasing with temperature and molecular weight. The crystallite contribution also increases over the range studied. Both fractions exhibit a significant, but reversible decrease in thickness on cooling the sample from the crystallization temperature to room temperature and recyling again. The change is more pronounced for 371,000 specimen in keeping with its lower crystallinity. The path dependence of lamellar dimensions has significant implications in the morphological characterization of polymers annealed or crystallized at one temperature and then measured at another one.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01412707
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    On Tanaka-Fillmore's kinetics swelling of gels (1989)
    Springer
    Colloid & polymer science 267 (1989), S. 179-183 
    Details
    ISSN: 1435-1536
    Keywords: Gel ; swelling ; kinetics ; diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Tanaka and Fillmore treated the swelling of a gel as a process where a crosslinked polymer network having been initially under uniform stress is expanded by osmotic pressure, sucking up the surrounding fluid medium. We point out that their physical reasoning is unnatural and leads to an unacceptable conclusion; we propose a more sound approach to the same problem. Our treatment assumes that the gel network is extended not by the osmotic pressure of the gel, but rather by the swelling pressure which is generated by the excess fluid penetrating in against the real nature of a polymer network that tends to shrink. The diffusion equation of the fluid, hence, plays a dominant role and gives the distribution of fluid concentration in contrast to Tanaka-Fillmore's scheme. The expression for the distribution of local strain in a spherical gel is deduced from the relation of mechanical balance between two forces, the one is due to the elasticity of the network and the other due to the gradient in the chemical potential of the fluid. The results obtained have forms analytically similar to Tanaka-Fillmore's, but are differ in the physical meanings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410357
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Diffusion of protons in silica hydrogel (1989)
    Springer
    Colloid & polymer science 267 (1989), S. 460-464 
    Details
    ISSN: 1435-1536
    Keywords: Diffusion ; silica gel ; kinetics ; surface area ; proton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The effect of preparation pH of silica hydrogel on the effective diffusion coefficient of protons in silica hydrogel (D e , m2/s), on surface area of silica gel (S, m2/s) and on particle size of silica gel (D p , mm) was studied. Silica hydrosols were obtained by adding water glass to sulfuric acid. The effective diffusion coefficient of proton in silica hydrogel was determined by the method of diffusion from silica hydrogel plane sheet to a stirred solution of a limited volume. A numerical solution was obtained for the diffusion equation using the Regula Falsi method. Regression analyses of experimental data were conducted. Diffusion of protons in silica hydrogel is a complicated process due to a decelerating effect of the porous structure of silica hydrogel and to the accelerating effects of slow ions such as Na+ and surface diffusion. The effective diffusion coefficient increased with surface area of silica gel, indicating the diffusion of protons on the surface of the silica particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410194
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Migration of small hydrophobic molecules between micelles in aqueous solution (1987)
    Springer
    Colloid & polymer science 74 (1987), S. 55-63 
    Details
    ISSN: 1435-1536
    Keywords: Triplet energy transfer ; micelle ; solubilization ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Triplet energy transfer from 9-methylanthracene to azulene or guajazulene has been used to probe the migration of azulenes between micelles in aqueous solution. The migration of the hydrophobic solutes between small ionic and nonionic micelles had the temperature dependence expected for a process controlled by diffusion through the intermicellar solution, although the rate in some cases was substantially less than calculated from the Smoluchowski equation. Under conditions in which the micelles grow into large, probably rod-like structures, there are severe difficulties in separating the inter- and intramicellar deactivation processes. The intermicellar migration was enhanced under these conditions, in cetyltrimethylammonium surfactants on addition of chlorate ions, and in hexaethylene glycol dodecylether at temperatures approaching the cloud-point. The mechanism of this migration is discussed and compared with pertinent results from micelle relaxation kinetics and surfactant self-diffusion measurements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01191012
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Dynamics of hydrogen bond complexes in polymer melts (1988)
    Springer
    Colloid & polymer science 266 (1988), S. 1102-1109 
    Details
    ISSN: 1435-1536
    Keywords: Hydrogenbonds ; reversiblenetworks ; complexformation ; complexdecomplexation ; kinetics ; viscoelasticity ; influence oftemperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The dynamics of hydrogen bond complex formation between functional groups which are attached to a polymer chain, is studied in the molten state. The concentration of complexes in the thermodynamic equilibrium is distorted by the application of a large oscillatory strain in the nonlinear viscoelastic regime. The relaxation back to the thermodynamic equilibrium is studied as a function of the temperature in the linear viscoelastic regime. From the mechanical response the kinetic analysis can be performed using a modified Doi-Edwards theory. Using the equilibrium constants obtained from IR-spectroscopy, the rate constants for complex formation and decomplexation are obtained. The temperature dependence is equivalent to the temperature dependence of the zero shear viscosity which implies that complex formation is a diffusion-controlled process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01414400
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...