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  • Polymer and Materials Science  (15,115)
  • Analytical Chemistry and Spectroscopy  (4,318)
  • 1980-1984  (19,433)
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  • 1
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Latexes based on styrene-glycidyl methacrylate copolymers were prepared by the emulsifier-free dispersion copolymerization technique. The main factors affecting the size and morphology of the latex particles and their distribution are the initiator concentration (K2S2O8), the total ionic strength of the aqueous phase, and the total monomer concentration. The existence of critical values for these variables was demonstrated. In the range in which these factors had values below the critical, the synthesized latex particles were spherical, homogeneous, and in varied sizes, depending on the abovementioned parameters in the range of 220-500 nm. Above the critical values of these variables the latex particles consisted of spherical aggregates of smaller particles. The reactive oxirane groups of the latex particles were modified later by hydrolysis, ammonolysis, reaction with Na2S, or periodic acid oxidation of the hydrolyzed or ammonolyzed forms of the latex particles.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Propellants, Explosives, Pyrotechnics 7 (1982), S. 107-109 
    ISSN: 0721-3115
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Mixtures of crystalline explosive and water have as a rule detonation properties different from the dry material. It has been shown that the character of those changes is closely related to the structure of the particles (crystals, granules) of the explosives. The critical diameters and detonation velocities have been measured for a range of explosive-water mixtures, and the results are interpreted in terms of the hotspot theory.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 11 (1980), S. 1-14 
    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: Material Stressing under Rolling Contact - Influence of Friction and Residual StressesMaterial stressing of parts in rolling contact is in the main made up by the normal load to be transmitted, by surface friction due to slippage of the body in rolling contact and by residual stresses. The effects of varying slippage rates are described as well as the additional influence of residual stresses on magnitude, position and direction of load.By the aid of mere mechanical reflections the formation of flat and steep White Bands can be interpreted which are observed in long-lived ball bearings subjected to high stresses. The report shows that residual stresses and friction must not be neglected when describing the material stressing by rolling contact. This especially applies to residual stresses originating from rolling contact.
    Notes: Die Werkstoffanstrengung bei Wälzkontakt ist im wesentlichen gegeben durch die zu übertragenden Normalkräfte, die Reibung an der Oberfläche (durch das Gleiten der beiden Wälzpartner) und durch die Eigenspannungen. Die Wirkung unterschiedlich großer Gleitanteile wird dargestellt und der zusätzliche Einfluß von Eigenspannungen auf die Höhe, Lage und Richtung der Beanspruchung ausgewiesen.Anhand rein mechanischer Betrachtungen läßt sich die Entstehung von flachen und steilen Weißen Bändern deuten, die in langlebigen, hochbeanspruchten Kugellagern beobachtet werden. Der Bericht zeigt, daß Eigenspannungen und Reibung keinesfalls bei der Beschreibung der Werkstoffanstrengung durch Wälzbeanspruchung vernachlässigt werden dürfen. Dies gilt insbesondere auch für die Eigenspannungen, die durch die Wälzbeanspruchung entstehen.
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  • 4
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    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 19 (1984), S. 573-576 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A detailed energy-resolved study of the fragmentation of CH2=CHCH(OH)CD2CD3 (1-d5) has been carried out using metastable ion studies and charge exchange techniques, combined with collision-induced dissociation studies to establish the structures of fragment ions. At low internal energies (metastable ions) the molecular ion of 1-d5 rearranges to the 3-pentanone structure and fragments by loss of C2H5 or C2D5 leading to the acyl structure, [CH3CH2C≡O]+ or [CD3CD2C≡O]+, for the fragment ion. However, with increasing internal energy of the molecular ion this rearrangement process decreases rapidly in importance and loss of C2D5 by direct cleavage, leading to [CH2=CHCH=OH]+, becomes the dominant fragmentation reaction. As a result the [C3H5O]+ ion seen in the electron impact mass spectrum of 1-penten-3-ol has predominantly the protonated acrolein structure.
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  • 5
    Electronic Resource
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 8 (1981), S. 312-315 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that under field desorption conditions some less volatile or non-volatile compounds such as oligosaccharides, sulphonic acids and fatty acids can be ionized below the threshold of field electron emission by clustering with anions. In all cases the sample, together with polyethylene oxide 4000, is dissolved in water. The source of the clustering anion is provided either by a small amount of a salt added to this solution (sugars) or by the compounds themselves (sulphonic and fatty acids). The solution is applied to unactivated and/or slightly activated 10 μm tungsten wire cathodes. Suitable clustering ions for the sugars appear to be [Cl]-, [NO3]- and to a lesser extent [Br]- and [I]-. Most of the sulphonic acids studied give rise to the formation of [Mn - H]- ions (n≤5), but their potassium salts yield only unclustered sulphonate anions. However, the addition of a small amount of LiCl to the mixture of benzene sulphonic acid and polyethylene oxide 4000 promotes the formation of clustered anions, [(M - H)2Li]- being by far the most abundant if activated cathodes are used. This addition of some LiCl is essential in the case of fatty acids: without LiCl no anions may be desorbed at all from activated wires, but with the presence of LiCl both [M - H]- and the most abundant [(M - H)2Li]- anions are easily generated.
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  • 6
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1983), S. 525-529 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The positive ion field desorption (FD) spectrum of arginine taken at the best anode temperature only contains a peak due to [M+H]+ ions. At higher emitter temperatures a considerable amount of fragmentation is induced and the [M+H—NH3]+ ions become most abundant. Specific 15N labelling reveals that the eliminated ammonia molecule, exclusively, contains one of the terminal nitrogen atoms of the guanidyl group. This also applies to the ammonia loss from metastably decomposing [M+H]+ ions. The positive ion fast atom bombardment (FAB) spectrum shows more fragmentation than the FD spectrum. In contrast with the FD results, the [M+H]+ ions generated upon FAB with ion lifetimes 〈10-6 s eliminate both ammonia containing one of the terminal nitrogen atoms of the guanidyl group and ammonia containing the α-amino group in the ratio of 1.35, as found by 15N labelling. The metastably decomposing [M+H]+ ions, however, eliminate only the former ammonia molecule. In the negative ion FD and FAB spectra no other peak than that corresponding to the [M—H]- ion is observed. Some attention has been paid to the thermal degradation of arginine on the basis of a few Curie-point pyrolysis experiments.
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  • 7
    ISSN: 0721-3115
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In order to examine whether and to what extent the ultrasonic multiple reflection technique can be used for detecting case/liner and liner/propellant debonds, measurements were performed on samples sawn from a particular case-bonded rocket motor consisting of a layer of 2.4 mm steel, a layer of 1,3 mm liner material (a polymer) and a thick layer of composite (AP/PU) propellant respectively. It was found that case/liner debonds could be traced reasonably well; liner/propellant debonds, however, could not be evidenced owing to strong quenching of the ultrasound in the liner. Investigations of the texture of the liner material with the aid of a scanning electron microscope proved the strong quenching in the liner to be mainly due to the presence of many voids with diameters of some 50 μm-200 μm which strongly disperse the sound beam.
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  • 8
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 169-171 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Glass capillary columns ; Trimethylsilyl derivatives ; Pregnant mares' urine estrogens ; Estrone-equilin separation ; OV-225, Silar 10C stationary phases ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Glass capillary columns coated with OV-225 and Silar 10C were used to analyze estrogens (as their trimethylsilyl derivatives) present in pregnant mares' urine. Such columns provide better resolution in a shorter time than the corresponding packed columns, as exemplified by the separation of estrone from equilin.
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  • 9
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    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1417-1422 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reversible isomerization of poly(chloromethylthiirane) and poly(3-chlorothietane) represents a new kind of polymer reaction and a new method of copolymer synthesis. In chloroform, in dichloromethane, or in nitrobenzene the reaction is well described by reversible first-order kinetics. A rate increase of ca. 40% on changing the solvent from chloroform to nitrobenzene is consistent with an isomerization mechanism that involves a rate-determining attack of the backbone sulfur atom on the neighboring carbon-chlorine bond and rapid ring-opening of the thiiranium ion intermediate by chloride ion.
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  • 10
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 25 (1980), S. 2681-2697 
    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 knowledge of some mechanical properties of twisted filament is necessary to predict properties of continuous-filament yarns. Retraction, strength, strain, and elastic properties of filaments are the chief characteristics. Assuming that the filament can be considered as a yarn made of fibers bounded together and then twisted, formulas for prediction of those properties were elaborated and then compared with the experimentally received values. Satisfactory agreement of computed results with experimental values is obtained if the changes in volume of filament at strain is taken into account.
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  • 11
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 28 (1983), S. 1277-1281 
    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 refractive indices, birefringence, and cross-sectional area of cotton fibers was measured using interference polarizing microscope constructed by M. Pluta. A new technique was suggested by realizing the measurements at the perpendicular position of the duplicated image of fiber to the interference fringe. The proposed procedure is a combination of modification of Hamza method and Pluta dual wavelength method, and it was possible to measure at once the three mentioned features of single fiber at one time.
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  • 12
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    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 19 (1981), S. 363-369 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complexes of acrylamide, methacrylamide, and their homologs with zinc, cadmium, and mercury halides were prepared by various methods. Molecular compositions, the nature of the coordination, and some physicochemical properties (melting points and initial decomposition temperatures) were determined. The effect of the chemical structure of particular monomers, metal ion, and halide on the possibility of complex formation and on the properties of the complex compounds were observed. Most of these complexes have not been described in the scientific literature.
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  • 13
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Radiation-induced solid-state polymerizations of complexes of N-tert-butylacrylamide, N-tert-amylacrylamide, and N-tert-hexylacrylamide with zinc chloride and zinc bromide have been studied. An accelerating effect of temperature and an inhibiting effect of oxygen on the polymerization process were observed. The activation energies have been established. The influence of monomer structure as well as the halide used on the polymerization rate have been discussed and some regularities have been pointed out. The polymers obtained show good solubilities in common solvents, which proves that they are not crosslinked.
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  • 14
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    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 22 (1984), S. 649-657 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 15
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    New York : Wiley-Blackwell
    Biopolymers 23 (1984), S. 695-705 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We studied films of poly(L-tyrosine) with hydrogen phosphate (residue/phosphate, 1:1) by ir spectroscopy. The influences of the alkali cations (Li+, Na+, K+) and of the degree of hydration were clarified. If Li+ ions are present, the OH⃛-OP hydrogen bonds formed in the dried films between the tyrosine OH groups and hydrogen phosphate are asymmetrical. The formation of hydrogen phosphate-hydrogen phosphate hydrogen bonds is prevented by the presence of the Li+ ions. With an increase in the degree of hydration, the tyrosine-phosphate bonds are not broken but become slightly stronger. Completely different behaviour is found if K+ ions are present. In dry films, the OH⃛-OP ⇌ O-⃛HOP hydrogen bonds formed between tyrosine and hydrogen phosphate show large proton polarizability. The tyrosine proton has a noticeable residence time at the acceptor O atom of the phosphate. The difference in the behaviour of the system with K+ ions when compared to the system with Li+ ions can be explained, since the hydrogen acceptor O atom of phosphate ions is more negatively charged due to the weaker influence of the K+ ions. Furthermore, POH⃛-OP hydrogen bonds between hydrogen phosphate molecules are formed. With an increase in the degree of hydration, the tyrosine-hydrogen phosphate hydrogen bonds are broken, all tyrosine protons are found at the tyrosine residues, and the -PO3- groupings are in a symmetrical environment, indicating that the K+ ions are removed from these groupings. If the degree of hydration increases further, hydrogen-bonded systems such as hydrogen phosphate-water-hydrogen phosphate are formed that show large proton polarizability due to collective proton motion. When Na+ ions are present, the OH⃛-OP ⇌ O-⃛HOP hydrogen bonds formed in dry films still show proton polarizability, but the residence time of the tyrosine proton at the phosphate is very short.
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  • 16
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    New York, NY [u.a.] : Wiley-Blackwell
    Fire and Materials 4 (1980), S. 17-27 
    ISSN: 0308-0501
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Architecture, Civil Engineering, Surveying , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A description is given of a model which predicts the motion of combustion products and fresh air caused by a fire located in one room of a two-room structure. The gas in each room is assumed to be divided into two homogeneous layers, a layer next to the ceiling which contains hot combustion products and one next to the floor which contains fresh air. The model predicts the motion of the interface separating these layers and the density of the hot layers as a function of time and an arbitrarily specified fire heat release rate.
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  • 17
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Influence of binary phase flow regimes on the action of sieve plates. Recognition of various flow regimes on sieve plates has greatly enhanced our understanding of the mode of action of these plates. When vapour flow dominates the liquid is dispersed into drops; this is the so-called „droplet regime“. In a second principal regime, liquid flow predominates and the vapour is dispersed into small bubbles; this is the „emulsion regime“. A transition region exists between these two principal regimes; it is called the „mixed regime“. The present paper attempts to demonstrate the relations between the flow regimes and the characteristics of sieve plates. It considers the structure of the binary phase layer, flow over the weir, axial mixing, entrainment of liquid, maximum loading (flooding), and efficiency.
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  • 18
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The phase behaviour of cellulose tricarbanilate (CTC) in ethyl methyl ketone (MEK) solutions was studied in the concentration range of 0,2 - 0,8 g/ml as a function of the temperature. By analyzing the textures in the polarizing microscope and by differential scanning calorimetry experiments several different phase transitions and mesophases were detected. At a concentration below 0,6 g/ml CTC in MEK, phase transitions were observed from the crystalline through a liquid crystalline (cholesteric) to the isotropic state. At concentrations higher than 0,6 g/ml, a different behaviour of the CTC solutions was detected and several transitions were found, but only the cholesteric-isotropic transition could be identified. The concentration dependence of the cholesteric-isotropic transitions was determined over the whole concentration range. The conformation of the CTC molecule was studied and a stiff, almost cylindrically shaped 3/2 helix with a repeat distance of 15,25 Å is proposed.
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  • 19
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 20
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    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Rapid Communications 5 (1984), S. 245-253 
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 21
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    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 6 (1984), S. 31-39 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: X-ray investigations have been carried out on crystalline and smectic polymers with polysiloxane backbones and mesogenic side groups attached to the main chain by flexible alkyl spacers. Fibers suitable for obtaining high-quality X-ray patterns of crystalline and smectic phases were produced by stretching samples, in which case the main chains were oriented or, with even better success, by alignment of the polymer side chains in a magnetic field. Ordered domains were detected for the crystalline and smectic state which were differently oriented depending on the fiber producing procedure. However, the packing of the chains within the domains is unaffected by the alignment procedure. The packing of the crystalline phase differs little from commonly known polymeric systems, and the smectic phase can be described with the same kind of packing in a less ordered state.
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  • 22
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    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Rapid Communications 2 (1981), S. 135-138 
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 23
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    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Rapid Communications 5 (1984), S. 567-571 
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 24
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    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 619-638 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A kinetic study of the propagation mechanism of the alternating copolymerization of styrene (St) with methyl methacrylate (MMA) in the presence of a complexing agent (diethylaluminum chloride, DEAC) in bulk and in tetrachloroethylene solutions at a molar ratio DEAC/MMA = 0.5 has been carried out. It has been shown that the copolymerization is a chain radical process characterized by a short active-center lifetime, bimolecular termination, and high rate of chain transfer to the complexed MMA. A kinetic scheme has been proposed for the propagation mechanism of alternating copolymerization in the presence of a complexing agent not requiring independent measurements of the equilibrium constant of complexation. It has been found that spontaneous and UV-initiated copolymerizations in the system have different mechanisms of initiation and a common mechanism of propagation. The propagation proceeds by addition of single monomers as well as donor-acceptor complexes of the comonomers to the propagation radicals, with the first mechanism being predominant. Inclusion of the monomers in the complex leads to an increase of the St reactivity and to a decrease of the MMA reactivity in propagation to the corresponding macroradicals in comparison with the reactivity of the free monomers. A number of kinetic and statistical parameters of the propagation reaction have been calculated.
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  • 25
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    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 19 (1981), S. 387-389 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 26
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    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 21 (1983), S. 315-318 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The analysis of the 1H NMR spectra of 2,8-dithia-1,5-diphosphabicyclo[3.3.0]octane, 2,8-dithia-1-phospha-5-azabicyclo[3.3.0]octane and 2,8-dithia-1-arsa-5-phosphabicyclo[3.3.0]octane is supported by means of 2D- J-resolved NMR measurements. The spectra suggest a preferred conformer with strong puckering of the fused five membered rings.
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  • 27
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    Journal of Polymer Science: Polymer Physics Edition 20 (1982), S. 815-823 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The osmotic compressibility of chemically crosslinked poly(vinyl acetate) (PVAc) gels in equilibrium with pure diluent has been determined by the method of decreasing equilibrium swelling in different swelling agents. The concentration dependence of the osmotic compressibility has been found to follow a scaling law with an exponent which was greater than that predicted by the mean-field theory. A comparison has been made between the elastic moduli determined by unidirectional deformation measurements and the compressional moduli obtained from the osmotic compressibility data.
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  • 28
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 4 (1981), S. 6-10 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Retention index calculation by correlation techniques ; Use of n-dialkyl sulphides as standards ; Use of selective detectors ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Retention indices were determined for a homologous series of n-dialkyl sulphides on three stationary phases (SE-30, OV-17 and XE-60) under isothermal and linear temperature programming conditions. Under these two different GC conditions, equations were derived for each of the three stationary phases which showed the dependence of retention index on the number of carbon atoms and the boiling points for a homologous series of n-dialkyl sulphides. The equation for the correlation isothermal retention index was shown to be applicable to the identification of n-dialkyl sulphides using linear temperature programming. It was found that the GC behaviour of n-dialkyl sulphides makes these compounds suitable for use as a standard series instead of n-alkanes for the calculation of retention indices in GC analysis in which detectors insensitive to n-alkanes are employed. The use of the homologous series of n-dialkyl sulphides for the calculation of sulphide retention indices can be great practical importance in the microanalysis of natural compounds. We have used this method successfully in the analysis of pesticides containing S-atoms.
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  • 29
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 306-309 
    ISSN: 0935-6304
    Keywords: Liquid chromatography, HPLC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for separation of low amounts of DHETX m. s. from human plasma, based on extraction and determination by high performance liquid chromatography with fluorimetric detection.
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  • 30
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    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 34 (1983), S. 514-519 
    ISSN: 0947-5117
    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: Influence of the substrate on the behaviour of corrosion protection coatings under impact loadLoading by impact produces two types of stress at the interface between coating and steel substrate. While the compressive stress remains essentially ineffective, the shear stress may lead to detachment of the coating in a circular area. The risk of damage, caused by loss of adhesion, can be modified, if special forms of profile are provided for at the steel substrate, particularly by blasting procedures. Shot blasting, however, leads to a structure, that hardly will improve the strength of adhesion. The treatment of the surface by grit blasting is by far more effective because the anti-corrosive coating can then virtually become clamped into the surface profile obtained in this way.
    Notes: Bei Stoßbelastung treten in der Grenzfläche zwischen Beschichtung und Stahluntergrund zwei Spannungstypen auf. Während davon die Kompressionsspannung ohne merklichen Einfluß bleibt, kommt es unter Wirkung der Scherspannung gegebenenfalls zu Schichtablösung auf kreisförmigem Bereich. Das wegen des Haftungsverlusts an solchen Stellen bestehende Schädigungsrisiko läßt sich durch spezielle Profilgestaltung des Stahluntergrundes modifizieren, vor allem durch Strahlbehandlung. Mit Rundkorn ausgeführt hinterläßt sie allerdings Strukturen, die relativ wenig zur Verbesserung des Haftvermögens beitragen. Hingegen vermögen sich Korrosionsschutzbeschichtungen erheblich fester in einem Oberflächenprofil zu verankern, das durch Behandlung mit scharfkantigem Strahlmittel zustande kommt.
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    Materials and Corrosion/Werkstoffe und Korrosion 33 (1982), S. 498-499 
    ISSN: 0947-5117
    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: Complexometric separation of surface layers for gravimetric determination of corrosion ratesA new method for determination of corrosion rates is described. It is concerned with the complete release of surface layers by using Titriplex-III, the anions of which are able to form complexes with the cations of the surface layer. This method is simple to handle, available even at small samples (3-4 g). It gives reliable results and allows further investigations of the layers. The procedure is described in detail for Zink, further examples are given for Fe, Al and Cu. The method is not available for metals which form very thin layers (Ti, Ni).
    Notes: Eine neue Methode der Deckschichtablösung als Teilschritt zur gravimetrischen Bestimmung der Korrosionsgeschwindigkeit wird vorgestellt. Sie beruht auf der Komplexbildung der Metallkationen mit Anionen von Titriplex-III. - Diese komplexometrische Methode ist einfach zu handhaben, liefert gut reproduzierbare Resultate, ist auch für kleine Proben (3-4 g) anwendbar und erlaubt die weitere Untersuchung der Deckschicht. - Am Beispiel des Zinks wird die Methode ausführlich beschrieben, Anwendungen an Fe, Al und Cu werden belegt. Die Methode versagt bei Metallen, die sehr dünne Schichten bilden (Ti, Ni).
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  • 32
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    Materials and Corrosion/Werkstoffe und Korrosion 33 (1982), S. 602-609 
    ISSN: 0947-5117
    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: Influence of CO2 on the corrosion kinetics of zinc in waterMechanism and kinetics of Zn and Zn/Fe corrosion in water containing various contents of CO2 is studied by impedance spectra completed by gravimetric corrosion measurements. Electrode impedance is clearly found to be a function of PCO2, the diffusion parameter is of essential importance. Ad as a function of PCO2 yields the same curves as the rest potential dependence on CO2 and moreover the gravimetrically measured corrosion velocity rises linearly with CO2. -Determination of corrosion velocity according to STERN-GEARY cannot be realized in the systems under investigation. -Experimental results lead to the conclusion that the main corrosion reaction takes place at the metal/layer-phase. The corrosion mechanism is discussed.
    Notes: Mechanismus und Kinetik der Korrosion von Zn und Zn/Fe (Fe-Gehalt: 0,52%, 0,96%, 2,96%) in Wässern unterschiedlicher CO2-Gehalte werden durch Aufnahme von Impedanzspektren und ergänzende Abtragsmessungen untersucht. Die Elektrodenimpedanz hängt deutlich vom PCO2 ab, die Warburg-Impedanz (Diffusion) Ad hat entscheidenden Einfluß. Die Ad-Kurven zeigen die gleiche Abhängigkeit von CO2 wie die Ruhepotentialverläufe; auch die gravimetrisch bestimmte Korrosionsgeschwindigkeit steigt linear mit PCO2 an. -Eine Anwendung der STERN-GEARY-Beziehung auf die vorliegenden Systeme ist nicht möglich. -Die Ergebnisse führen zu dem Schluß, daß an der Phasengrenze Metall/Deckschicht die wesentliche Reaktion stattfindet. -Der Mechanismus der Zn-Korrosion in CO2-haltigen Wässern wird diskutiert.
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  • 33
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    Journal of Polymer Science: Polymer Physics Edition 18 (1980), S. 157-160 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 34
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    Journal of Polymer Science: Polymer Physics Edition 18 (1980), S. 897-901 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 35
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    Journal of Polymer Science: Polymer Physics Edition 20 (1982), S. 1453-1464 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The pressure-volume-temperature (PVT) relationships of bisphenol-A polycarbonate, polyarylate, and phenoxy were studied at pressures to 1800 kg/cm2 and in both the glassy and melt states. Earlier data on polysulfone are included in the analysis and discussion of the results. All four polymers contain the bisphenol-A residue in their repeat unit, together with a moiety of varying complexity, and are therefore somewhat related. At the glass transition, equations of the Ehrenfest type hold, provided the pressure dependence of the glass transition temperature is defined from the line obtained by intersecting the quasiequilibrium PVT relationship of the glass with the equilibrium PVT surface of the melt. The Prigogine-Defay ratio r = ΔκΔCp/TgVg(Δα)2 at P = O is unity within experimental error for all four polymers. The melt data were fitted successfully to the Simha-Somcynsky theory. Molecular parameters deduced from the reducing parameters vary in a reasonable manner among these four related polymers, lending support to the foundations of the theory.
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  • 36
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    Journal of Polymer Science: Polymer Physics Edition 20 (1982), S. 1385-1397 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The pressure-volume-temperature (PVT) properties of blends of poly(2,6-dimethyl-1,4-phenylene ether) (PPO) with polystyrene (PS) have been studied experimentally in both the glassy and melt states at 0, 20, 40, 50, 60, 80, and 100% PPO content. In all compositions a strong glass transition was observed varying linearly with composition. For all but the 40% PPO composition this was the only transition, indicating molecular compatibility of the components in these blends. The 40% PPO composition showed a very weak second transition near the glass transition of pure PS. A small amount of phase separation may have occurred in this blend. The data for the glassy and melt states were fitted to an empirical equation of state based on the Tait equation. The volume of the melts at constant pressure and temperature showed a virtually linear dependence on composition. Any negative excess volume of mixing compatible with the data would have to be very small, smaller than expected from previous measurements in the glassy state. Various properties relating to the glassy and melt states and to the glass transition were evaluated and are discussed as a function of composition. It was found that most properties of the glasses could not be modeled by simple functions of composition.
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  • 37
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 2033-2045 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of absorbed doses of ionizing radiation up to 2MGy in the presence of air on the melting behavior of high- and low-density polyethylene was analyzed from data obtained by differential scanning calorimetry. Thermal measurements were made during the first melting after irradiation. The first melting temperature of polyethylene irradiated in air decreased with increasing absorbed dose. Above approximately 0.6 MGy bimodal endotherms were observed for high-density polyethylene. The heat of fusion remained unchanged after irradiation in air for absorbed doses of less than 2 MGy. Bimodal endotherms were not obtained for low density polyethylene samples irradiated in air. The changes in melting temperature and the appearance of bimodal endotherms are related to the radiation chemistry of polyethylene in the presence of oxygen.
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 2017-2032 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of ionizing radiation on the melting behavior of high-density and low-density polyethylene was examined with data obtained by differential scanning calorimetry. Melting temperatures and fusion endotherms were obtained after absorbed doses of gamma radiation up to 3 MGy. The changes in melting temperatures and heat of fusion for the first and second meltings are related to the radiation chemistry of polyethylene. The changes in the first melting temperature are caused by radiation-induced links that decrease the melt entropy and increase the flod surface free-energy-per-unit area of chain-folded polyethylene crystals. These effects are dependent on the lamellar thickness distribution and on the types of links formed (intramolecular or intermolecular). The changes in melting temperature and heat of fusion obtained in the second melting are related to the inhibition of crystallization caused by the presence of radiation-induced links.
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1763-1771 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of methanethiol (CH3SH) on the radiation chemistry of low-density polyethylene was examined by using intrinsic viscosity measurements, low-angle laser light scattering, and infrared spectrophotometry. Radiation-induced intermolecular linking was found to be almost completely inhibited in low-density polyethylene by the presence of less than one weight percent of CH3SH during irradiation. The net yield of transvinylene was also reduced, probably by reaction of transvinylenes with methylthiyl radicals (CH3S). The inhibition of radiation-induced intermolecular linking by CH3SH demonstrates that linking is a relatively slow process involving reactions of alkyl free radicals, and that prompt intermolecular links caused by rapid ionic, ion-molecule, or “hot hydrogen” processes are not significant in the radiation chemistry of low-density polyethylene.
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  • 40
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    Chemie Ingenieur Technik - CIT 53 (1981), S. 600-606 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Description / Table of Contents: New approaches in flotational processing and waste water treatment in the chemical industry. Flotation has not yet become universally accepted in the chemical industry as a separation technique for the solids/liquid system. This article attempts to discover the reason why. It also presents possibilities enhancing the attractiveness of the flotation technique for recovery of materials and waste water purification in the chemical industry. A brief indication of the phenomena exploited by the flotation technique is followed by a discussion of chemical engineering aspects of this technique in ore and coal flotation and in mechanical waste water purification. A flotation cell without stirrer is presented, as has been designed specifically for the chemical industry. In conclusion, some flotation tasks performed with a laboratory version of this type of cell are presented and discussed. They show that the flotation technique can be a favourable alternative to classical separation techniques in many solids/liquid and liquid/liquid separation tasks, and should therefore be considered in future for appropriate separation problems (particle size ca. 100 μm, solids content ≤ 20 g/l).
    Notes: Die Flotation hat sich in der chemischen Industrie als ein Trennverfahren für das System fest/flüssig bisher noch nicht durchgesetzt. In der vorliegenden Arbeit wird versucht, dafür eine Erklärung zu finden. Gleichzeitig werden Möglichkeiten aufgezeigt, die die Flotationstechnik zur Werkstoff-Rückgewinnung und Abwasserreinigung in der chemischen Industrie attraktiv machen könnten. Nach Hinweisen auf die Phänomene, deren sich die Flotationstechnik bedient, werden die verfahrenstechnischen Aspekte dieser Technik bei der Erzund Kohleflotation bzw. bei der mechanischen Abwasserreinigung besprochen. Es wird eine rührerlose Flotationszelle vorgestellt, die speziell für die Belange der chemischen Industrie entwickelt worden ist. Abschließend werden einige Flotationsaufgaben, die mit einer Laborausführung dieses Zellentyps durchgeführt worden sind, vorgestellt und besprochen. Sie zeigen, daß die Flotationstechnik bei vielen Trennaufgaben in den Stoffsystemen fest/flüssig und flüssig/flüssig eine günstige Alternative zu den klassischen Trennverfahren sein kann und sie daher künftig bei entsprechenden Trennproblemen (Teilchengröße ≤ 100 μm, Feststoffgehalt ≤ 20 g/l) in Erwägung gezogen werden sollte.
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    Chemie Ingenieur Technik - CIT 54 (1982), S. 939-952 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Chemical engineering of aerobic waste water treatment - developments and trends. The present article deals with chemical engineering problems encountered in biological waste water treatment, as seen in research reports published during the last 5 to 10 years. It is seen that important advances in our biological and engineering knowledge of the biological degradation of organic wastes, relating to residence time distribution, concentration of biomass, and the temperature in the activation process have not been given sufficiently consistent attention in practice. Controversial views and possible solutions are indicated. Immobilization (especially with activated charcoal as carrier) offers certain advantages for raising the concentration of biomass in the activation space, this also facilitating separation of the biomass from the purified water. Flotation could offer an alternative. Disposal of the excess activated sludge is nowadays accomplished largely by anaerobic fermentation (bioconversion); the engineering of this step was developed in the 1930's and should be updated at the earliest possible opportunity. This would enhance the appeal of the process because the energetic potential of the biomass could then be fully utilized.
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    Chemie Ingenieur Technik - CIT 56 (1984), S. 839-844 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Design and dimensions of a mechanical defoamer. This paper presents a newly developed powerful mechanical defoamer which exploits centrifugal force and, thanks to circular channels, also Coriolis force for destruction of foam. It is incorporated into containers such that the expelled foam concentrate is deflected by the lid without producing fresh foam. Model experiments with three geometrically similar but different sized laboratory models led to dimensionaltheoretically formulated process-relations of the defoamer for various material systems (five chemical foamers, two biological substrates). Such process-relations represent a reliable basis for design and dimensions of the defoamer presented, on the one hand, and permit determination of an „intermediate characteristic“, having the dimensions of acceleration, which represents the mechanical degradability of the foam.
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  • 43
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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    Chemie Ingenieur Technik - CIT 55 (1983), S. 363-372 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Model scale-up in chemical engineering. Similarity theory and the theory of models based thereon are working tools which permit reasonable planning of experiments, their execution with a minimum of effort, and their evaluation in such a way as to provide reliable information about the design and the operating conditions of the technical plant - provided these methods are used in good time and in the proper manner. A brief introduction to the problems involved and to the methodology of similarity theory is provided by the introductory section and the first example. Four more problems and their solutions according to similarity theory serve to answer questions concerning the size of the experimental scale, the choice of material system used in the experiment, and the problem of scale-up under conditions of partial similarity. Two of these examples clearly illustrate that an inadequate knowledge of the material parameters (e. g. for foams and slurries) necessitates model measurements on the technical system with a change of scale.
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  • 45
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    Journal of High Resolution Chromatography 7 (1984), S. 370-374 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Trace analysis ; On-column injection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Large sample volume on-column injection (up to 250 μL) of n-pentane solutions of halogenated hydrocarbons has been employed for the direct measurement of both low-boiling and high-boiling compounds in what is essentially a single run. Two-bonded phase, fused-silica capillary columns are joined in series, through which the low-boiling compounds are first chromatographed and detected with an electron capture detector. High-boiling compounds are then trapped in a section joining the two columns, and subsequently chromatographed in the second column, using the same detector. This procedure permits analysis at the ppt level.
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    Journal of Applied Polymer Science 25 (1980), S. 963-966 
    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
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    Journal of Polymer Science: Polymer Physics Edition 19 (1981), S. 1177-1186 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Molecular relaxation in a series of polyethylene samples has been investigated by radiothermo-luminescence. Polyethylene structure is discussed in terms of different modes of molecular mobility in different structural regions. Each of the low temperature transitions is assigned to a certain structure region and structural unit(s). The influence of different polyethylene molecular parameters and processing conditions on its structure and mechanical properties is also considered.
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    Journal of Polymer Science: Polymer Letters Edition 21 (1983), S. 571-574 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 49
    ISSN: 0308-0501
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Architecture, Civil Engineering, Surveying , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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    Materials and Corrosion/Werkstoffe und Korrosion 32 (1981), S. 324-331 
    ISSN: 0947-5117
    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: Case histories on surgical implants and their causesSince the first use of chromium nickel molybdenum steels for implants in the thirties rapid progress has been made in the development of stainless steels. Until today these improvements have scarcely been taken into consideration by material standards for implants.In agreement with the characteristic potentials for localized corrosion a statistical evaluation of failures shows that pitting, crevice corrosion and corrosion fatigue as a result from the latter can easily be avoided by higher contents of chromium and molybdenum. Steels in accordance with these requirements are specified in all standards and would solely from the economic point of view justify their use.
    Notes: Seit dem erstmaligen Einsatz von Chrom-Nickel-Molybdän-Stählen für Implantate in den 30er Jahren, hat die Entwicklung der chemisch beständigen Stähle große Fortschritte gemacht, die in den Werkstoffnormen für Implantate bis heute kaum einen Niederschlag gefunden haben.Eine statistische Auswertung von Schadensfällen läßt in Übereinstimmung mit der Lage der charakteristischen Potentiale erkennen, daß Lochfraß, Spaltkorrosion und die dadurch verursachten Korrosionsdauerbrüche durch höhere Chrom- und Molybdängehalte leicht vermieden werden können. Stähle, die diesen Anforderungen gerecht werden, sind in allen Normen enthalten und würden allein vom wirtschaftlichen Standpunkt ihren Einsatz rechtfertigen.
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    Biological Mass Spectrometry 17 (1982), S. 74-78 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The fragmentation pathways of RDX in chemical ionization mass spectrometry have been rationalized, using data from different reagent gases, including CD4 and iso-C4D10. The dependence of spectra taken with different gases on the acid strength of the reactant ions in the gases is accounted for.
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    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Unter Anwendung einer Eichbeziehung für die linearen und cyclischen individuellen Analoga wurde die hydrolytische Copolykondensation von Methylvinyl- und Methylphenyldichlorsilanen in Abhängigkeit von Monomerverhältnis, Lösungsmittel und Temperatur untersucht. Die Hydrolyse in Alkohol führt zur vorzugsweisen Bildung linearer höhermolekularer Oligomere.
    Notes: By the method of exclusion liquid chromatography and application of calibration relationship for linear and cyclic individual analoges, the hydrolytic copolycondensation of methylvinyl- and methylphenyldichlorsilanes was investigated in dependence on solvent and temperature. Hydrolysis by alcohol leads mainly to the formation of linear high molecular weight oligomers.
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  • 53
    ISSN: 0009-286X
    Keywords: Extraktion ; Tropfenbildung ; Stoffaustausch ; Flüssigkeits-Szintillation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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    Materials and Corrosion/Werkstoffe und Korrosion 35 (1984), S. 1-7 
    ISSN: 0947-5117
    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: Untersuchung des Korrosionsverhaltens einer NiCrMo-Legierung in PNP Helium mittels Röntgendiffraktion und Elektronenstrahl-MikroanalyseProben der Nickelbasis-Legierung Nimonic 86 wurden in PNP-500-artigem Helium während 1000 h bei 650, 750, 850, 900 und 950°C ausgelagert. Röntgendiffraktion zeigte nach der Wämebehandlung 5 neu gebildete Phasen an den Probenoberflächen. Ihre Bestimmung ergab (1) einen Spinell Cr2MnO4 (für T ≤ 850°C), dessen Al- und Ti-Gehalt mit zunehmender Temperatur zunimmt, (2) ein Sesquioxid Cr2O3 (für T 〉 900°C) mit einem beträchtlichen Mn-Gehalt für T ≤ 850°C, (3) ein ≠1 Oxid Ni2Mo3O (hauptsächlich bei 750°C) mit geringem Fe-Gehalt, (4) ein ≠1 Karbid (Ni, Cr, Si)3Mo3C (für T ≤ 750°C), (5) Cr23C6(für T ≤ 850°C) mit etwas Mo.
    Notes: Samples of the nickel base alloy Nimonic 86 were exposed to PNP-500 type helium for 1000 h at 650, 750, 850, 900 and 950°C. X-ray diffraction showed 5 additional phases, formed at the sample surfaces during the heat treatment. They were shown to be: (1) a spinel Cr2MnO4 (at T ≤ 850°C) containing increasing amounts of Al and Ti with increasing temperature, (2) a sesquioxide Cr2O3 (at T ≥ 900°C) containing substantial amounts of Mn for T ≤ 850°C, (3) an ≠1 oxide Ni3Mo3SO (mainly at 750°C) containing some Fe, (4) an ≠1 carbide (Ni, Cr, Si)3Mo3C (at T ≤ 750°C), (5) Cr23C6 (at T ≤ 850°C) containing some Mo.
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  • 55
    ISSN: 0009-286X
    Keywords: Flüssig/Flüssig-Extraktion ; pulsierter Siebbodenextraktor ; Anfahrverhalten ; mathematische Simulation ; Dynamik ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 56
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 57
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 58
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The kinetics of thermal degradation of polyethylene terephthalate containing antimony and zinc derivatives as polycondensation catalysts was investigated in an open and a closed stirred system by the increase of carboxyl groups. Based on kinetic data the allowed residence times in the processing stages of PETP melts are derived. Further, the activation entropies are calculated and the mechanism of thermal splitting of ester bonds catalyzed by metal derivatives is discussed. The suggested reaction mechanism is supported by kinetic data obtained in model experiments with ethylene glycol, diethylene glycol and butane diol-1,4-dibenzoate as well as by thermal degradation of polybutyleneterephthalate.
    Notes: Die Kinetik des thermischen Abbaus von Polyethylenterephthalat, das Antimon-bzw. Zinkderivate als Polykondensationskatalysator enthält, wurde in einem geschlossenen und in einem offenen, durchmischten System anhand der Carboxylgruppenzunahme untersucht. Aus den kinetischen Kenndaten werden Ableitungen für zulässige Verweilzeiten bei der Verarbeitung von PETP-Schmelzen getroffen, zum anderen wird auf Grundlage der aus diesen Kennwerten berechneten Aktivierungsentropien der Mechanismus der durch Metallderivate katalysierten thermischen Esterspaltung diskutiert. Der postulierte Reaktionsmechanismus wird durch die kinetischen Daten der Modellversuche mit Ethylenglykol-, Diethylenglykol-und Butandiol-1,4-dibenzoat sowie des thermischen Abbaus von Polybutylenterephthalat gestützt.
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  • 59
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    Acta Polymerica 34 (1983), S. 666-666 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 60
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    Acta Polymerica 34 (1983), S. 767-767 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 61
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    Acta Polymerica 35 (1984), S. 252-252 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
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  • 62
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: No Abstract
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  • 63
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    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 18 (1984), S. 927-938 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Filamentous carbon fiber is an extremely compatible biomaterial. It does not corrode and elicits almost no foreign body response. In addition, this material is an efficient electrical conductor in vivo. These desirable characteristics suggest that carbon fiber may be of use as an electrode material for the stimulation of bone and/or soft tissue growth. This possibility has been investigated in a well established laboratory animal model. When used as a cathode material in conjunction with an implantable constant direct current device, carbon fiber was shown to be an effective electrode material for the stimulation of bone and fibrous tissue within the medullary canal of the tibia of the rabbit. Further, adjustment of current levels appear to allow some selectivity in terms of the amount and type of tissue produced. Currents in the 1 m̈A range produced a maximum amount of bone, whereas a 20 μA current produced a maximum amount of fibrous tissue. Intermediate current levels produced a proportional mix of bone and soft tissue.
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  • 64
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    Journal of Polymer Science: Polymer Letters Edition 22 (1984), S. 52-53 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 65
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    Journal of Applied Polymer Science 28 (1983), S. 1751-1765 
    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 new mathematical model is presented for the description of certain types of diluent diffusion (migration) through diluent-polymer systems. The model describes anomalous diluent transport into a container of finite volume, and it incorporates mass transfer limitations at the polymer/extractant interface. The extractant is assumed to diffuse slowly or negligibly into the polymer. The model is applied to experimental data obtained with two plasticizers, di(2-ethyl-n-hexyl) phthalate and benzyl butyl phthalate, migrating from poly(viny1 chloride) to water.
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  • 66
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    Angewandte Makromolekulare Chemie 116 (1983), S. 77-88 
    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: Mit Di-(2-ethylhexyl)-phthalat weichgemachtes PVC wurde mit einer Reihe von homologen Alkoholen in Kontakt gebracht, um Wanderungserscheinungen des Weichmachers zu untersuchen. Wachsende Mengen an ausgewandertem Weichmacher wurden mit zunehmender Molekülgröße des Pènetriermittels erhalten. Die Penetriermittel wirkten als Extraktionsmittel, und der Wanderungsprozeß wurde von der Bildung einer glasigen Schicht an der Polymer/Penetriermittel-Grenzfläche begleitet.
    Notes: Migration phenomena were investigated for poly(vinyl chloride) plasticized with di-(2-ethyl-hexyl)phthalate and placed in contact with a series of homologous alcohols as penetrants. An increasing amount of migrating plasticizer was obtained as the size of the penetrant increased. The penetrants behaved as extracting media and the migration process was accompanied by the formation of a glassy layer at the polymer/penetrant interface.
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  • 67
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    Biopolymers 23 (1984), S. 2067-2081 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Resonance Raman spectra of the nucleoside 5′-monophosphates UMP, CMP, AMP, and GMP have been obtained with 266- and 213-nm radiation, the fourth and fifth harmonics of a Nd:YAG laser. The 266-nm radiation is resonant with the states giving rise to the first absorption band of the bases. The resulting spectra are in agreement with those reported previously using similar wavelength excitation but are generally of better quality. The 213-nm radiation is resonant with those states giving rise to the second strong absorption band of the bases. The spectra obtained with this wavelength show several new features relative to the 266-nm spectra, including strong enhancement of modes of the pyrimidines with a character similar to the e2g ν8 mode of benzene, relative enhancement of ring modes at 1580 and 729 cm-1 in AMP, and strong enhancement of the 1670-cm-1 C = O mode of GMP. These enhancements are discussed in terms of previously reported preresonance behavior and predicted intensities based on CNDO bond-order changes and normal-mode calculations. The results of a preliminary study of the effect of the interaction of GMP with cis-dichlorodiammineplatinum(II) on the 213-nm resonance Raman spectrum is also discussed.
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  • 68
    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: Siliciumnitrid: Gefüge, Eigenschaften und neue HerstellungsverfahrenAnhand der Korrelation zwischen einigen wichtigen Gefügeparametern und verschiedenen mechanischen, thermischen und thermomechanischen Eigenschaften von heißgepreßtem und reaktionsgesintertem Siliciumnitrid wird die Forderung nach einer weiteren Verbesserung der Eigenschaften und nach einer ökonomischeren Herstellung von Siliciumnitrid durch Anwendung neuer Verfahren aufgezeigt. Die Aussichten und Probleme bei den verschiedenen neuen Verfahren, dem Sintern von verdichteten Si3N4 - Pulverkörpern, dem Nachsintern von reaktionsgesintertem Siliciumnitrid und den verschiedenen Methoden des heißisostatischen Pressens, werden diskutiert.Die Arbeit ist in 2 Teile unterteilt:Teil I: Einfluß des Gefüges auf die mechanischen, thermischen und thermomechanischen Eigenschaften von Siliciumnitrid.Teil II: Neue Herstellungsverfahren von Siliciumnitrid.In Teil I wird der Zusammenhang zwischen Gefüge und verschiedenen mechanischen, thermischen und thermomechanischen Eigenschaften von heißgepreßtem und reaktionsgesintertem Siliciumnitrid diskutiert, wie Bruchfestigkeit, Temperaturleitfähigkeit und Thermoschockverhalten. Aufbauend auf dieser Korrelation werden die heutigen Grenzen von Siliciumnitrid für eine breitere Anwendung sowie die Möglichkeiten für eine Optimierung dieser Materialgruppe dargelegt. Diese Diskussion zeigt sehr deutlich, daß es notwendig ist, einige wichtige Eigenschaften weiter zu verbessern und neue Herstellungsverfahren zu entwickeln. In Teil II der Arbeit werden die Entwicklungsrichtungen dieser neuen Herstellungsverfahren für Siliciumnitrid aufgezeigt. Es wird ein Überblick über die in jüngster Zeit erzielten Fortschritte bei der Anwendung dieser Verfahren gegeben. Als Beispiel für ein neues Herstellungsverfahren werden Ergebnisse vom heißisostatischen Pressen von reaktionsgesintertem Siliciumnitrid diskutiert.
    Notes: Based on the correlation of some essential microstructural parameters and various mechanical, thermal and thermo-mechanical properties of hot-pressed and reaction-bonded silicon nitride, the demand for further improving the properties of silicon nitride and for developing a more economical fabrication of silicon nitride by applying new processing techniques is indicated. Aspects and problem areas of various new techniques, such as sintering of Si3N4-powder compacts and post-sintering of reaction-bonded silicon nitride as well as the various routes of hot-isostatic pressing, are discussed. The paper is divided into two parts:Part I: Microstructural effects on mechanical, thermal and thermomechanical properties of silicon nitride.Part II: New processing techniques of silicon nitride.In part I the relationship between microstructure and various mechanical, thermal and thermo-mechanical properties of hot-pressed and reaction-bonded silicon nitride, such as fracture strength, thermal diffusivity and thermal shock resistance, is discussed. On the basis of this correlation today's limits of silicon nitride regarding a broader application, and the possibilities for optimizing this material group are outlined. This discussion demonstrates the necessity of further improving some important properties and of developing new processing techniques. In part II the development lines of these new techniques for silicon nitride processing are discussed and a survey is given of recent progresses in the use of those techniques. As an example of a new processing technique, results of hot-isostatic pressing of reaction-bonded silicon nitride are presented in more detail.
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  • 69
    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: Teil II: Neue Herstellungstechniken von SiliciumnitridIn Teil I wurde der Zusammenhang zwischen Gefüge und verschiedenen mechanischen, thermischen und thermomechanischen Eigenschaften von heißgepreßtem und reaktionsgesintertem Siliciumnitrid diskutiert, wie Bruchfestigkeit, Temperaturleitfähigkeit und Thermoschockverhalten. Aufbauend auf dieser Korrelation wurden die heutigen Grenzen von Siliciumnitrid für eine breitere Anwendung sowie die Möglichkeiten für eine Optimierung dieser Materialgruppe dargelegt. Diese Diskussion zeigt sehr deutlich, daß es notwendig ist, einige wichtige Eigenschaften weiter zu verbessern und neue Herstellungs-techniken zu entwickeln. In Teil II der Arbeit werden die Entwicklungsrichtungen dieser neuen Herstellungstechniken für Siliciumnitrid aufgezeigt. Es wird ein Überblick über die in jüngster Zeit erzielten Fortschritte bei der Anwendung dieser Techniken gegeben. Als Beispiel einer neuen Herstellungstechnik werden Ergebnisse vom heißisostatischen Pressen von reaktionsgesintertem Siliciumnitrid diskutiert.
    Notes: In part I of this paper the relationship between microstructure and various mechanical, thermal and thermo-mechanical properties of hot-pressed and reaction-bonded silicon nitride, such as fracture strength, thermal diffusivity and thermal shock resistance, was discussed. On the basis of this correlation today's limits of silicon nitride regarding a broader application and the possibilities for optimizing this material group were outlined. This discussion demonstrates the necessity of further improving some important properties and of developing new processing techniques. In part II the development lines of these new techniques for silicon nitride processing are discussed and a survey is given of recent progresses in the use of those techniques. As an example of a new processing technique, results of hot-isostatic pressing of reaction-bonded silicon nitride are presented in more detail.
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  • 70
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    Die Makromolekulare Chemie 184 (1983), S. 1497-1508 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The potentiometric titration of syndiotactic methacrylic acid/dimethacryloylamine (MMA-MAI) copolymers is investigated. In contrast to copolymers studied before, MAA-MAI copolymers possess a highly syndiotactic backbone structure, a compositional statistics known from NMR-measurements, and a cyclic structure as a part of the chain. The statistics of the MAA-units and MAI-rings is nearly random with respect to the formation of imide rings, the rings introducing a trans and a gauche conformation for each ring. Plots of the apparent pK (pKapp) versus the degree of ionization α, or versus log [(1- α)/ α], indicate a change from a relatively dense coil (a-state) to an extended coil (b-state) when α is increased. The decisive parameter for pKapp in the b-state and for the conformational transition of the a-state to the b-state is the charge density on the chain β. The transition takes place for all copolymer compositions in an interval of Δβ ≈1 but the interval is situated at lower absolute values of β for the copolymers with higher contents of MAI-rings. The Δβ at lower β may be either due to a decrease in intramolecular attraction or to a higher electrostatic repulsion. The free enthalpy of the conformational transition is, however, approximately the same for copolymers with different MAI contents. This constancy of the free enthalpy points to a conformational transition which is energetically not much different for the MAA- and the MAI-units in the chain.
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  • 71
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology , Physics
    Notes: The chemical structure of syndiotactic methacrylic acid-dimethacryloylimide (MAA-MAI) copolymers is studied by the NMR-spectra of products obtained by polymeranalogous reactions and from MAA-MAI copolymers prepared according to a different route. The kinetics of formation of the imide rings is compared with kinetic equations, confirming thereby the random formation of rings along the chain. 13C NMR spectra of MAA-MAI copolymers depend on the degree of neutralization, α, in aqueous solution and show large changes for the carbonyl resonance region. Resolution into triads is found in organic solvents, whereas in aqueous solutions there is splitting into pentads on going from α = 0 to α = 1. The pentad assignment is made by observing the movement of the peaks with changing α and by comparison with pentad probabilities derived by a Monte-Carlo simulation. The great changes in the chemical shift are caused to a large extent by a change in the charge of the carboxyl groups. Discontinuous changes in charge, conformation, and solvation are not found.
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  • 72
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    Die Makromolekulare Chemie 185 (1984), S. 1855-1866 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A convenient method for binding saccharides to natural and synthetic substances, polymers and low molecular weight compounds, consists in coupling via an amide linkage. For this purpose aldonolactone or amino groups are introduced at the reducting end of the saccharides which allows coupling to a great variety of amino and carboxyl groups containing compounds. Purification with the usual ion-exchange resins based on polystyrene proved unsatisfactory for oligosaccharides due to adsorption effects and reduced ion-exchange capacity. Excellent results on each step of conversion are obtained by chromatography on a cross-linked poly(acrylamide) gel (Bio-Gel P-4 and P-10) containing a small amount of carboxylic groups introduced by moderate saponification. The new procedure combining the effect of molecular size fractionation and ion-exchange chromatography offers a wide field of application.
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    Die Makromolekulare Chemie, Rapid Communications 5 (1984), S. 363-371 
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 74
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 75
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    Biopolymers 19 (1980), S. 1415-1434 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The energy of interaction of a spermine molecule with the A- and B-forms of DNA has been calculated, assuming that the molecule of spermine is fixed in the narrow groove of the DNA helix with the formation of hydrogen bonds between the amino groups of spermine and the phosphate groups of DNA. The atom-atom potentials method was used. Optimal structures for the A-DNA-spermine and B-DNA-spermine complexes are suggested. It is shown that, in agreement with the experimental data, the interaction of the spermine molecule with the A-DNA is energetically more favorable than that with the B-DNA. Two main factors are responsible for this: (1) the distance between neighboring phosphates of the chain in A-DNA (which is about 1 Å less than that in B-DNA) corresponds better to the distance between the amino groups of the propyl part of spermine; and (2) the orientation of phosphate groups in A-DNA inside the groove is preferable for complex formation with spermine to the outside groove arrangement of the phosphates in B-DNA. These conclusions are further confirmed by the calculations for DNA-propane diamine complexes.
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  • 76
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
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    Topics: Chemistry and Pharmacology
    Notes: The theory of adsorption of semistiff chains on a planar surface developed by the authors previously has been used to consider the helix-coil transition in single-stranded macromolecule interacting with an adsorbent plane. The cases of nonselective interaction when the adsorption energy is independent of the unit conformation (a) and selective interaction with only helical (b) or coiled (c) sequences active in adsorption were investigated. In case (b) the existence of secondary structure favors chain bonding to the surface. This leads to the increase in the stability of the helical state and complete polypeptide chain spiralization. The profile of the conformational helix-coil transition acquires an asymmetrical shape inherent to the second-order phase transition.In case (c) the bonding of a partially helical chain to the surface is similar to the adsorption of Gaussian coils and is accompanied by the destruction of secondary structure, this destruction being appreciable even if the helical state in space was favorable.
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    Biopolymers 21 (1982), S. 1021-1036 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A strict analytical theory has been developed describing the behavior of a model lattice polymer chain of arbitrary stiffness in a slitlike pore at polymer-adsorbent interaction energies -ε. The thermodynamic characteristics of the system were calculated. It was shown that the transition of the macromolecule from the solution volume inside a pore occurs by the first-order phase transition with evolution of latent heat of adsorption. The transition point -ε = -εc is determined by the chain stiffness and is independent of the pore width D. It is shown that in the precritical range, -ε 〈 -εc, the free energy ΔF of the macromolecules in the pores is adequately described by the universal dependence ΔF = ΔF(D*/A), where D* is some effective pore width depending on the value of -ε, and A is the length of the Kuhn segment. At high attraction energies, -ε ≫ -εc, the macromolecules are bonded to the pore walls by a great number of units and their free energy depends only on -ε and the chain stiffness, ΔF = ΔF(A, ε). Close to the critical energy -ε ≃ -εc (transition range), ΔF is determined by both the stiffness of the macromolecule and the pore width D: ΔF ∼ A2D-1 for fairly high values of A and D. The possibilities of using porous media as protein stabilizers are discussed, and the value of the stabilizing effect depending on the chain stiffness is estimated.
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    Die Makromolekulare Chemie 182 (1981), S. 3625-3638 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The supermolecular structure of melt-crystallized segmented copoly(ether ester)s based on poly(tetramethylene terephthalate) and poly(tetramethylene oxide) is investigated by polarizing microscopy and electron microscopic techniques. Spherulites are formed on isothermal crystallization at supercoolings ΔTu 〈 30°C. The spherulites recrystallize to form dendritic structures on further annealing at higher temperatures. The spherulites and dendrites are builtup from lamellae which exhibit little variation concerning the thickness of their crystalline core. The internal phase boundaries in these systems are made visible with a newly developed staining method. A network of interlocked individual lamellae is formed on rapid quenching of the melt films. Row crystallization (shish-kebabs) is observed, if the melt is sheared during the crystallization. It is concluded from these observations that the chemical structure of the segmented copolymers bears little relevance for the supermolecular structure of these materials except for the thickness of the crystalline core of the lamellae which seems to be related to the molecular length of the hard segment sequences occurring with the highest concentration in the sample.
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    Die Makromolekulare Chemie 182 (1981), S. 3639-3651 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The isothermal melt crystallization of three segmented copoly(ether ester)s based on PBT as the hard and PTMO as the soft segments differing in their hard segment content was investigated. The kinetics of crystallization was studied using polarizing microscopy and DSC. Two regimes of crystallization were observed. Spherulitic structures of low crystallinity are formed via predominantly athermal nucleation in regime I at supercoolings ΔTu 〈 30°C. Ill-defined aggregations of lamellae grow at ΔTu 〉 30°C. The crystallization follows an apparent Avrami-equation; the Avrami-constants cannot be explained in terms of a simple model. The structure of the samples was investigated by SAXS and compared to the structure of samples crystallized by rapid quenching and subsequent annealing. Much higher long spacings are obtained on isothermal crystallization. The long spacing increases with decreasing ΔTu. It increases at constant ΔTu with decreasing average hard segment length contrary to the samples crystallized by subsequent annealing of the quenched melt. In this case polymers differing in composition do not differ with regard to the long spacing obtained at constant ΔTu. The modulus in the Hookean-range as derived from stress-strain curves at T 〉 Tg does not reflect the details of the morphology or chain architecture but it is found to depend logarithmically on the volume fraction of crystallinity in the sample. Data of pure PBT are described by the same relationship.
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    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 595-603 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Dynamic mechanical and optical transparency methods were used to investigate the compatibility of a series of blends of sulfonated cis-1,4-polyisoprene and styrene/4-vinylpyridine copolymers. It was found that compatibilization occurs at a degree of substitution less than 5%. It is suggested that proton transfer from the sulfonic acid group to vinyl pyridine, which results in the generation of specific anion-cation interactions, is responsible for the compatibilization, since the removal of ionic interactions through esterification destroys the compatibility.
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 657-671 
    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: Acetyl sulfate was used as sulfonating agent for the sulfonation of cis-1,4-polyisoprene. IR and NMR spectra showed that the sulfonation was accompanied by extensive cyclization. A series of DSC and loss tangent studies of both the sodium salts and the methyl esters was undertaken. It was found that cyclization exerts a profound influence on the micrbrownian segmental motion of the hydrocarbon matrix and is the dominant factor in raising the glass transition temperatures. However, the differences in the mechanical properties between salts and esters suggest that the presence of ions does influence the melt viscosities and shear moduli of the sulfonated cyclized rubbers; this influence can be minimized by esterification or water absorption. It is seen that the ionic effects in these materials are quite typical of those encountered in a wide range of other ionomers.
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  • 82
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 3313-3320 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alkyl substitution in a series of main chain, liquid crystal polyesters strongly depressed their glass temperatures, melting points, clearing points, and mesophase thermal stabilities. Polymers with pendant n-alkyl substituents eight carbon atoms or longer did not form a liquid crystal phase.
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  • 83
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    Journal of High Resolution Chromatography 3 (1980), S. 440-446 
    ISSN: 0935-6304
    Keywords: High performance thin-layer chromatography ; β-adrenoceptor blocking drugs ; Continuous development ; Multiple development ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High performance thin-layer chromatography was used for the separation of nine therapeutically important and structurally similar β-adrenoceptor blocking drugs on silica gel plates. In situ scanning of the plate in the reflectance mode gave detection limits in the low nanogram range depending on the individual drug and the wavelength selected for its determination. Scanning the HPTLC plate at several wavelengths can be used to aid the identification of partially resolved components. Continuous development and continuous multiple development techniques are compared for the simultaneous separation of the drug mixture.
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  • 84
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    Journal of Applied Polymer Science 28 (1983), S. 2467-2472 
    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 effect of pressure P up to 2.5 × 103 MPa on the dielectric constant ε and conductivity G of a number of conjugated polymers doped by iodine has been studied. Polyphenylacetylene prepared with FeAcAc, polyphenylacetylene obtained with Ziegler catalyst, anionic polydiphenylacetylene, and polydiphenylbutadiene were chosen for investigation. It has been found that after doping the values ε and G increase and strongly depend on P. The possible mechanism of this phenomenon has been discussed.
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  • 85
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    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 929-937 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of high pressure or the combined action of high pressure and shear deformation on the conductivity G and capacitance C of metal-free polyphthalocyanines (PPhCs), differing in macromolecular size, order, and degree of crosslinking, has been studied. It has been found that both G and C increase with compression. A similar phenomenon is observed under the combined action of high pressure and shear deformation on PPhC, but in this case the critical pressure needed for change in G is lower than that observed in uniaxial compression experiments. Spectroscopic investigations show that the effects of pressure and deformation on the electrophysical properties of samples under load is not connected with changes in the chemical structure of PPhC, but appear to be due to the change in the average distance between the regions of continuous conjugation. The sizes of such regions may be increased by preliminary thermal treatment.
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  • 86
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    Journal of Polymer Science: Polymer Physics Edition 22 (1984), S. 117-127 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Wide-line NMR has been used in an investigation of noncrystalline (amorphous) regions in oriented semicrystalline polymers. Nylon 6 was chosen as a model material. The tie-chain length distribution function, the fraction of tie chains in the total number of chains in the crystallite cross section, and the relative number of taut tie chains have been determined. The data on the tie-chain length distribution are used in discussing specific features of vitrification of the amorphous regions in oriented polymers and in prediction macroscopic mechanical properties.
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  • 87
    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: Butadiene and isoprene were copolymerized with LnCl3-ROH-AIR3 catalytic system. The products obtained were confirmed to be copolymers by their glass transition temperatures and characteristic pyrolytic chromatograms, etc. The equation for copolymerization rate may be expressed as Rp = Kp(M)2(cat). The rate constants of copolymerization, activation energy, and monomer reactivity ratios for catalytic systems containing various rare earth elements in III-B family and different solvents were determined. It was found that the reactivity ratio of butadiene was greater than that of isoprene and r1r2 near 1, and the composition and microstructure of copolymers were not much affected by variation of polymerization conditions. Both monomer repeat units in the copolymers had cis-1,4 contents above 95%, which is a distinguishing feature of coordination polymerization with the lanthanide catalyst system.
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  • 88
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The stereoregularity of polydienes is almost the same in regard to the individual elements of the lanthanide series, whereas the activity of the Ln catalysts in diene polymerization varies from one to the other within the series. The latter may be attributed to the difference in the number of electrons that occupy the 4f orbitals. It has been proved that the polymerization of dienes with Ln catalysts under certain conditions proceeds by a “living polymer” mechanism. With regard to the polymerization of butadiene, the most active catalyst is a Nd3+species a new binary system of NdCl3-3ROH + AlR3 has been discovered. The cis- 1,4 content in polybutadiene is about 97% and the 1,2 content, less than 1%. For the polymerization of isoprene with a Nd3+ catalyst system, the effects of ligand and alkyl groups in AIR3 on cis-1,4 content (ca. 95%) in polyisoprene can be neglected. For the copolymerization of butadiene and isoprene, the cis-1,4 contents of these two monomeric units in the copolymer are greater than 95% the reactivity ratios r1 and r2 are determined. and the Tg's of the copolymers of various compositions deviate slightly from the calculated values for random copolymers. A linear relationship exists between the yield strength from the stress-strain curve of Ln-polvbutadiene and its [n] This relationship is verified by Ln-polyisoprene and natural rubber but different slopes are obtained
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  • 89
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    Journal of Polymer Science: Polymer Letters Edition 20 (1982), S. 411-416 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 90
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    Journal of Polymer Science: Polymer Letters Edition 20 (1982), S. 244-245 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 91
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    Die Makromolekulare Chemie 6 (1984), S. 227-233 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Carbosiloxane polymers of cyclolinear structure have been synthesized by hydrosilylation reaction. The structure of the elementary unit is determined by the structure of organocyclotetrasiloxanes, which have groups in 1,3- and 1,5-positions. The investigation of the polyaddition reaction has shown that cyclotetrasiloxanes with 1,5-position of reactive groups yield polymers with molecular weights till 25·104, contrary to tetrasiloxanes with 1,3-position. This is connected with a higher reactivity of the former cyclosiloxane. The morphology of the polymers depends on the linking mode of cyclotetrasiloxanes in the polymer chain. The X-ray and electron-microscopic investigation have shown that the polymer from I + III crystallize during polyaddition; the degree of crystallinity of these polymers is 30 and 50%, respectively. The thermomechanical properties of the resulting cyclolinear polymers have been also investigated.
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  • 92
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Bimodal networks consisting of very short and relatively long poiydimethylsiloxane (PDMS) chains were studied from 30 to -52°C in an attempt to elucidate the anomalous increases in modulus [f*] exhibited by such elastomeric materials at high elongations. Temperature was found to have very little effect on (i) the elongation at which the upturn in [f*] becomes discernible, (ii) the elongation at which rupture occurs, and (iii) the total increase in [f*] up to the rupture point. The standard force-temperature (“thermoelastic”) plots were linear, but gave values of the energetic contribution to the total force which were significantly smaller than those universally obtained on unimodal, long-chain PDMS networks. Birefringence-temperature relations were also found to be linear, and yielded values of the optical-configuration parameter and its temperature coefficient which were in satisfactory agreement with the corresponding values reported for unimodal PDMS networks. These results indicate that even at very low temperatures the observed increases in modulus (and consequent improvements in ultimate strength) are due to non-Gaussian effects arising from limited chain extensibility, rather than from intermolecular reinforcing effects such as strain-induced crystallization.
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  • 93
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 225-238 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High molecular weight polysilane copolymers which contain the units in the title were prepared in high yield by sodium coupling the corresponding organodichlorosilanes in toluene. These copolymers are highly soluble in common solvents and can be drawn into fibers or formed into films by molding or casting. They are also photoactive.
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  • 94
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    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 159-170 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Formable silane copolymers that contain dimethylsilylene units were synthesized and characterized. These polymers have high molecular weights and appreciable solubility in common solvents, can be molded or cast into films or drawn into fibers, and are photoactive.
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  • 95
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 3115-3127 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this article we report the synthesis of a polyurea containing the chelating ligand bipyridine and concentrate on some of the catalytic properties of its palladium complexes.
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  • 96
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    Acta Polymerica 35 (1984), S. 153-156 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Analyse der Beziehungen zwischen der Struktur von Komplexen lithiumorganischer Verbindungen mit Elektronendonatoren und ihrer Reaktivität sowie dem regulierenden Einfluß auf die Struktur der Polymerkette ermöglicht es, eine Klassifizierung der Elektronendonatoren und der entsprechenden Komplexe, die als aktive Zentren in Erscheinung treten, vorzuschlagen.
    Notes: The analysis of a relationship between the structure of complexes of organolithium compounds with electron donors and their reactivity and regulating effect on the structure of the polymer chain made it possible to suggest a classification of electron donors and the corresponding complexes playing the part of active centres.
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  • 97
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    Biological Mass Spectrometry 19 (1984), S. 645-646 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 98
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    Chemie Ingenieur Technik - CIT 56 (1984), S. 144-145 
    ISSN: 0009-286X
    Keywords: Zweiphasenströmung ; Phasenseparation ; Rohrverzweigung ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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    Journal of Polymer Science: Polymer Letters Edition 20 (1982), S. 671-672 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal of Polymer Science: Polymer Letters Edition 18 (1980), S. 141-141 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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