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  • Polymer and Materials Science  (1,709)
  • Biochemistry and Biotechnology  (149)
  • 1970-1974  (1,858)
  • 1974  (1,858)
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  • 1970-1974  (1,858)
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  • 1
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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  • 2
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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  • 3
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
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  • 5
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 11
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 12
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The growth of a mixed methane-utilizing culture in a continuous flow fermenter has been studied under both methane and oxygen limitation. Small additions of methanol have been shown to inhibit the methane-utilizing moiety in the culture and it has been shown that the Hyphomicrobium sp. in the mixed culture removes any inhibitory methanol. The interaction between the methane-utilizing Pseudomonas sp., and the Hyphomicrobium sp. has been explained and a model of the continuous mixed culture under oxygen limitation has been formulated. Qualitative predictions of transient phenomena by the model have been verified experimentally.
    Additional Material: 8 Ill.
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  • 13
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 61-76 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Polysaccharide was synthesized by Aureobasidium pullulans (or Pullularia pullulans) 2552 in a sucrose medium. The field apparent viscosity of the culture medium from shake flask experiments rose to 24,500 cP and then dropped toward its initial value as the fermentation progressed. The magnitude of the maximum apparent viscosity depended on the initial pH of the fermentation broth. The inoculum age influenced the cultivation period before which the maximum viscosity was reached. Rheograms of the fermentation broths showed a change in viscosity behavior from Newtonian to pseudoplastic, and then toward Newtonian characteristics during the fermentation. The calculated non-Newtonian index was found to be a sensitive factor for the indication of the non-Newtonian behavior. Such behavior could not be detected from rheograms. Viscosity profiles of polysaccharide isolated from various stages of the fermentation showed a change from Newtonian to pseudoplastic behavior depending on the concentration (0-2%) of polysaccharide.
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  • 14
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 385-396 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Trypsin (EC 3.4.4.4) was immobilized in low yield on aminoalkylsilylated magnetite (Fe3O4). Better results were obtained when trypsin was immobilized by crosslinking with glutaraldehyde on magnetite. The preparation contained 36 mg protein/g magnetite and the enzyme retained 46% and 11% of esterase and proteolytic activity. Immobilized trypsin was more heat stable than trypsin. Invertase (β-D-fructofuranoside fructohydrolase, EC 3.2.1.26) was cross-linked on magnetite with glutaraldehyde in low yield due to the inactivation of the enzyme. However in the presence of 1% sucrose, the total activity recovered was 79% of the initial activity and the preparation contained 4.4 mg/g of active invertase. Immobilized invertase was less active than invertase when acting on oligosaccharides of the raffinose family. The immobilized enzymes could be easily recovered, from solutions or suspensions, magnetically.
    Additional Material: 7 Ill.
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  • 15
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Tab.
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  • 16
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A fiber-optic retroreflective turbidimeter has been developed to automatically and continuously assay the cell concentration in a fermentor by measuring the turbidity of the solution as a function of the light scattered at 180° to the incident light. The output signal is nearly directly proportional to the cell concentration in a fermentor when the sample stream contains from 0 to more than 50 g of cells per liter (wet weight). The device consists of a bifurcated fiber-optics light pipe with its distal end inserted into a flow cell through which the material to be analyzed passes. A light source on one proximal branch of the light pipe illuminates the sample stream; light that is back-scattered from participates in the stream re-enters the light pipe and is returned to a photodetector on the other proximal branch of the light pipe. A signal conditioning system connected to the optical head by a cable provides gain and zero adjustment.
    Additional Material: 8 Ill.
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  • 17
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 555-557 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 18
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 285-287 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Tab.
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  • 19
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The enzyme β-galactosidase (lactose) obtained from several microbial sources was immobilized on zirconia-coated porous glass particles. The immobilized enzymes were characterized by determining pH profiles, kinetic constants, thermal profiles, and operationalhalf-lives in lactose and whey ultrafiltrate solutions. Studies were carried out on continuous reactor performance, and enzyme requirements for scale-up were estimated. Lactose or whey hydrolyzed by this technique could find use commercially as a sweetener in a number of dairy products.
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  • 20
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 987-990 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 21
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 991-995 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 22
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1004-1004 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
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  • 23
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1399-1406 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
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  • 24
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 25
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An apparatus is described for the rapid measurement and recording of methanogenic activity in anaerobic fermentations, and its application is demonstrated in the evaluation of the anaerobic contact process, using pear waste. The method is based on recording the rate of manometer liquid displacement in a Warburgtype vessel by means of optical sensors, appropriate electronic circuitry, and an event marking recorder or time-interval printer. Optimum conditions for measuring methanogenic activity included a pH of 6.7-6.9, a final phosphate buffer concentration of 0.07-015M, and formic and acetic acid contents of over 500 and 200 mg/liter, respectively. In comparisons of fermenter liquid and settled effluent, methanogenic activity can be assumed to be proportional to the number of methane formers present. The apparatus should be generally useful in recording rates of gas production or consumption.
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  • 26
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Immobilized glucoamylase, invertase, and β-galactosidase were prepared by using N-vinylpyrrolidone monomer (VP) under γ-ray irradiation. The enzyme-VP solutions were gelled by irradiation with 2.9 Mrad and the added enzymes were almost completely entrapped. Activity losses on entrapping were 55% for the VP-glucoamylase gel, and more than 90% in the case of VP-invertase and VP-β-galactosidase gels. No leakage of enzyme from these gels could be detected within 1 hr. The VP-glucoamylase gel was capable of hydrolyzing dextrin (mol wt 10,400) to glucose and the glucose equivalent was equal to that obtain able with native enzyme. The optimum temperature, heat stability, pH activity curve, and pH stability of VP-glucoamylase gel were slightly inferior to those of native enzyme, while Km was a little larger than that of native enzyme.
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  • 27
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1549-1551 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 28
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 29
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Films of highly polymerized collagen, prepared in industrial conditions, were chosen for surface covalent binding of enzymes because of their insolubility, mechanical resistance, proteic nature, hydrophilic properties and for their abundance in chemically activable —COOH. Untanned films, previously acid- methylated, were activated by acyl azide formation. After removal of reagents by repeated washing, the coupling of enzyme was performed by immersion of the activated film in the enzyme solutions (2 to 3 hr, 0°C). The procedure is particularly mild since the enzymes never come into contact with chemical reagents, and thus avoid all denaturing processes. All the enzymes tested were successfully bound: glutamate dehydrogenase, lactate dehydrogenase, malate dehydrogenase, aspartate aminotransferase, glutamate pyruvate transaminase, creatine kinase, hexokinase, trypsin, and urease. As tested with aspartate amino transferase, enzymatic activity remained constant for months (100% after 5 months) in spite of repeated use of the film at 30°C, washing and storage in buffer at 4°C between assays.
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  • 30
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: β-Galactosidase has been purified from an ammonium sulfate precipitate of E. coli strain ML308 by biospecific adsorption on a column of agarose gel substituted with p-aminophenyl-β-D-thiogalactopyranoside. The system described using a 1.8 liter column has a useful processing capacity of 3.8 × 106 units of β-galactosidase per 2 hr cycle. This corresponds to about 5 g of pure enzyme. An electromechanical timing device operates a set of six solenoid valves and carries out a preset program consisting of sample application, washing, and elation operations.
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  • 31
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 32
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Efforts were made to eliminate the influence of other factors as far as possible in order to obtain reliable results on the effects of oxygen on the growth of baker's yeast. A cultivation method is presented which permits the study of the effects of aeration intensity under conditions where the influence of catabolite repression is eliminated. A completely synthetic medium with glucose as the only carbon and energy source is also described.The capacity of yeast to perform aerobic metabolism varies when cultivated under different intensities of aeration. A clear maximum is observed for growth with 10% oxygen in the aerating gas mixture. Under conditions where catabolite repression does not function yeast has the potential for oxidative metabolism even under oxygen-limited growth. The main agent controlling the ability of yeast to support growth using only the oxidative metabolism is the available oxygen.At high oxygen tensions the metabolism is disturbed.
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  • 33
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: System response data for step changes in input tracer concentration have been obtained for two different impeller agitated continuous flow mixing systems containing aqueous polysaccharide solutions. The vessel volumes were 1.6 and 10.9 liters. Polysaccharide concentration, dilution rate, and impeller speed were varied according to a plan devised using dimensional analysis and assuming that bulk motion is the predominant mass transport mechanism in the system. The data show that this is not true and that serious errors may occur if scale-up calculations are based on assuming that bulk motion predominates. Under the operating conditions used, perfect mixing was not observed.
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  • 34
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The overall rate of reaction of buffered gel-immobilized glucose oxidase particles is described by means of an enzyme rate equation which relates the overall reaction rate of a particle to the free solution characteristics of the enzyme, the effective diffusivity of the limiting substrate in the gel, the characteristic particle size, and the limiting substrate concentration adjacent to the gel surface. This equation accounts quantitatively for the limitation of the overall rate of reaction by substrate diffusion, and it is used to illustrate the influence of the system parameters, i. e., particle size, enzyme concentration, and pH, on the extent of the diffusional resistance associated with gel-immobilized glucose oxidase particles.The enzyme rate equation is generally applicable to those enzymes whose kinetics approximately follow Michaelis-Menten form when in free solution.
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  • 35
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1359-1372 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A column reactor with an annular cross section was formed by rolling up DEAE cellulose paper and a screening spacer. Glucoamylase was attached by ion adsorption. For the spacer used, pressure drop was very low, suggesting that this form may be useful with feed streams that are not completely particle-free. Tests of this reactor at the high substrate concentrations characteristic of commercial reactors showed very little diffusional resistance, exhibiting zero-order behavior over most of the concentration range. At low concentrations, the reactor had an apparent “half-order” behavior caused by diffusional limitation in the paper. In this range, flow rate influenced the reaction rate, showing that mass transfer in the main stream also is a contributing factor in this range. Because of the high concentrations and the low Michaelis constant (0.0011 M) the reactor does not show first-order behavior, even at very high conversions. The design of a plant-scale reactor was formulated from these data. The increase in the quantity of enzyme necessary to compensate for the effects of diffusion was only a few percent.Two reactors were formed with sheets nonporous to the enzyme, binding the enzyme with cyanogen bromide after forming the reactor. The amount of enzyme bound was about one monolayer, and there appeared to be no diffusional limitations, even at low substrate concentrations.
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  • 36
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1413-1418 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
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  • 37
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The enzymatic synthesis of nucleoside-5′-monophosphates from purineriboside, 6-mercapto-purine riboside, 6-methylmercapto-purine riboside, 6-chloro-purine riboside, tubercidin, 8-aza-adenosine, and 3′-deoxy-adenosine is described in gram scale. The synthesis is catalyzed by a phosphotransferase from carrots and uses phenylphosphate as phosphate donor. The reaction products are purified on QAE-Sephadex A25 columns. The large scale preparation of the enzyme is also reported.
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  • 38
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Ribulose-1,5-diphosphate carboxylase from spinach has been bound to arylamine porous glass with a diazo linkage and to alklamine porous glass with glutaraldehyde. Stability at elevated temperatures and responses to changes of pH and ribulose-1,5-diphosphate, Mg2+, and dithiothreitol concentrations were not significantly different from the soluble enzyme, though stability at 4°C was somewhat improved.
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  • 39
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1537-1544 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aminoacylase was covalently coupled to several porous ceramic type carriers and studied for durability under operating conditions. These studies indicate that it should be possible to develop a commercially economic system based on ceramic carriers for the resolution of racemic mixtures of amino acids.
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  • 40
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1557-1564 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 41
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The microbial cells of Pseudomonas putida ATCC 4359 were immobilized by entrapment in a polyacrylamide gel lattice. Enzymatic properties of L-arginine deiminase of the immobilized P. putida cells were investigated and compared with those of the intact cells. The permeability of substrate or product through the cell wall und the heat stability of the enzyme were increased by immobilization of the cells. No difference was observed between pH activity curves of the intact and immobilized cells. The optimal temperature for the formation of L-citrulline was 37°C for the intact cells and 55° C for the immobilized cells.When an aqueous solution of 0.5M L-arginine hydrochloride (pH 6.0) was passed through a column packed with the immobilized cells at a flow rate of SV = 0.26 at 37°C, L-arginine was completely converted to L-citrulline. The enzyme activity of the column was stable and the continuous production of L-citrulline could be carried out at 37°C for the month by using the immobilized cell column. From the effluent of the column, L-citrulline was easily obtained in a good yield.
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  • 42
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1675-1680 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
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  • 43
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    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 35 (1974), S. 9-25 
    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: A short survey on heterocyclic glycidyl compounds is given and synthesis of 1,3-bis-(hydantoin-3-yl)-propan-2-ol-derivatives from hydantoins and epichlorhydrin is described. These syntheses and possible intermediates are discussed. Preparation of triglycidylcompounds from these substances is given and properties after curing are mentioned.
    Notes: Nach einem kurzen überblick über heterocyclische Polyglycidylverbindungen wird die Synthese von verschiedenen 1,3-Bis-(hydantoin-3-yl-)propan-2-ol-Derivaten aus Hydantoinen und Epichlorhydrin beschrieben; dabei werden verschiedene Herstellungswege und mögliche Zwischenprodukte diskutiert. Die Darstellung von Triglycidylderivaten der neuen Substanzen wird gezeigt, und Eigenschaften der neuen Epoxide werden erwähnt.
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  • 44
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    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 35 (1974), S. 27-38 
    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: The pyrolysis-gaschromatographic investigation of polybutadienes with various amounts of 1.2 units shows the occurence of some characteristic splitting products, which give information on the 1.2-content in dependence of the sequence length distribution. The method is also applicable to crosslinked polybutadienes.
    Notes: Die pyrolyse-gaschromatographische Untersuchung von Polybutadienen mit verschiedenem 1,2-Gehlt zeigt, daß mehrere charakteristische Spaltprodukte auftreten, die eine Aussage über den 1,2-Anteil in Abhängigkeit von der Sequenzlängenverteilung ermöglichen. Die Methode eignet sich auch für die Erkennung der zugrundeliegenden Polymeren bei vernetzten Polybutadienen.
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  • 45
    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: Structural changes are investigated which occur in mixtures of polyethylene with low and high density by radiation with γ-rays. It is established by electron microscopy that up to certain doses the rays cause structuring in the clean polymers and also in the mixtures. At greater radiation doses (10 Mrad) degradation and crazes are obtained. These processes are in direct dependance on the contents of the mixtures and are connected with their crystal structure. By X-ray investigations the change in the crystal structure of the mixture is studied. The destruction of the polymer chains is proved by IR-spectroscopy.
    Notes: Es wurden Strukturänderungen, die in Mischungen aus Polyäthylen mit niederer und hoher Dichte bei Bestrahlung mit γ-Strahlen auftreten, untersucht. Mit Hilfe der Elektronenmikroskopie wurde festgestellt, daß dieγ-Strahlen bis zu bestimmten Dosen eine Strukturierung bei den Reinpolymeren und deren Mischungen hervorrufen. Bei größeren Bestrahlungsdosen (10 Mrad) treten Abbau- und Rißbildungsprozesse auf. Diese Prozesse hängen von der Zusammensetzung der Mischung ab und sind mit der Kristallinität verbunden. Mittels röntgenographischer Untersuchungen wurde die änderung der Kristallinität studiert. Der Abbau der Polymerketten wird mittels IR-Spektroskopie bewiesen.
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  • 46
    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: In the work presented, the adsorption of polystyrene (PS) from cyclohexane (25°C, 36°C), dioxane (15°C, 36°C) and methylethylketone (15°C, 36°C), the adsorption of polyethyleneglycol (PEG) from H2O and methanol (25°C) and the adsorption of polyvinylpyrrolidone from H2O (25°C) was investigated by means of ellipsometry. Chrominium covered glass-slides, prepared by high-vacuum technic, were used as adsorbent. From the thickness, concentration and adsorbed amount measured it can be followed, that the polar PEG is adsorbed in a principle different manner than the unpolar PS. PEG prefers to adsorb in a flat uncoiled manner, while PS is adsorbed in a coil-form conformation.
    Notes: In der vorliegenden Arbeit wurde die Adsorption von Polystyrol aus Cyclohexan (25°C, 36°C), Dioxan (15°C, 36°C) und Methyläthylketon (15°C, 36°C), die Adsorption von Polyäthylenglycol aus Wasser und Methanol (25°C) und die Adsorption von Polyvinylpyrrolidon aus Wasser (25°C) an hochvakuumbedampften Chromspiegeln mit Hilfe der Ellipsometrie untersucht. Aus den gemessenen Schichtdicken, Schichtkonzentrationen und adsorbierten Mengen ist zu folgern, daß das polare Polyäthylenglycol (PäG) in prinzipiell anderer Weise adsorbiert als das unpolare Polystyrol. PäG adsorbiert in flach aufliegender entknäuelter Form, das unpolare Polystyrol dagegen in knäuelförmiger Konformation.
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  • 47
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 35 (1974), S. 75-83 
    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: The degree of mutual penetration of random coils close to the ϑ-point was investigated by evaluation of the maximum conversion of the reaction of a OH-groups containing polymethylmethacrylate (PMMA) with a COCl-groups containing PMMA in a mixture of benzene and n-hexane. We have found, that the degree of coil penetration in ϑ-solvents has the same value as in good solvents, namely 5 to 20% of the coil volume with a polymer concentration of 10 to 30 wt.-%. Sterical factors are discussed as the reason for the small mutual penetration of the coils. Because of 1-T/ϑ = 0 no energy barrier can be present.
    Notes: Durch Reaktion eines OH-Gruppen enthaltenden Polymethacrylsäuremethylesters (PMMA) mit einer äquivalenten Menge eines COCl-Gruppen enthaltenden PMMA und Bestimmung des maximal erreichbaren Umsatzes in Benzol-n-Hexan-Gemischen wurde der Grad der gegenseitigen Knäueldurchdringung in der Nähe des ϑ-Zustandes untersucht. Es wurde gefunden, daß der Grad der Knäueldurchdringung im ϑ-Zustand in der gleichen Größenordnung liegt wie in guten Lösungsmitteln, nämlich von 5 bis 20% des Knäuelvolumens, steigend in einem Konzentrationsbereich von 10 bis 30 Gew.-% Polymeres in der Lösung. Sterische Faktoren werden als Ursache dafür angesehen, daß die Knäuel trotz des Fehlens einer Energieschwelle (1-T/ϑ = 0) sich kaum durchdringen und nur in den Kontaktzonen verzahnt sind.
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  • 48
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Ein Reaktionsmechanismus wird für die ABS-Pfropfcopolymerisation vorgeschlagen. Bei der Polymerisation von Styrol und Acrylnitril in Gegenwart von Polybutadien kann das Reaktionsmedium von Anfang an als heterogen betrachtet werden. Dadurch können zwei parallel verlaufende Polymerisationen angenommen werden, wovon eine wesentlich zu gepfropftem und die andere zu ungepfropftem SAN führt.Der Verlauf dieser beiden Reaktionen wird dargestellt unter Berücksichtigung der preferentiellen Solvatation des Polybutadiens durch Styrol und durch den Initiator und unter der Annahme, daß das Pfropfcopolymere wesentlich durch die Polybutadienmakroradikale initiiert wird.Kinetische Untersuchungen auf dieser Grundlage ergaben folgende Beziehungen für die Polymerisationsgeschwindigkeit, die Pfropfausbeute und die Molekulargewichte: Sowohl für ABS als auch für die Pfropfung von Styrol auf Naturkautschuk führen diese Beziehungen zu einer guten Ubereinstimmung mit den experimentellen Werten.
    Notes: Un mécanisme de la réaction de greffage est proposé dans le cas des copolyméres ABS. Pour la polymérisation du styrène et de l'acrylonitrile en présence de polybutadiène, on peut considérer le milieu réactionnel comme hétérogène dès le début de la réaction. Le processus de greffage peut donc être dissocié en deux réactions parallèles, l'une conduisant essentiellement au SAN greffé et l'autre au SAN non fixé sur le polybutadiène (SAN libre).L'évolution des réactions en présence est donnée, en tenant compte de la solvatation préférentielle du polybutadiène par le styrène et le promoteur, et en considérant que le copolymère greffé est essentiellement formé à partir des macroradicaux sur le polybutadiène (créés par interaction avec les radicaux primaires).L'étude cinétique effectuée sur ces bases a permis d'établir des relations relatives à la vitesse de polymérisation, au taux de greffage et aux masses moléculaires. Un très bon accord est obtenu entre les valeurs expérimentales et celles calculées d'après ces relations, aussi bien dans le cas des ABS que dans celui du greffage de polystyrène sur caoutchouc naturel.
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  • 49
    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: Das Kupfer-Chelat aus Polyacrylhydrazid wurde hergestellt, und seine Struktur und Eigenschaften wurden untersucht. Es wurde gefunden, daß das Chelat-Polymere bei Raumtemperatur in wäßriger Dioxanlösung die radikalische Polymerisation von Methylmethacrylat initiiert. Die Gesch windigkeit der durch das polymere Chelatintiierten Polymerisation ist viel größer als die durch monomere Modell-Chelate wie z. B. Essigsäurehydrazid ausgelösten. Die katalytische Aktivität des Chelates aus Polyacrylhydrazid beruht wahrscheinlich auf dessen Polyelektrolyt-Charakter. Die Einflüsse der Konzentration an Kupfer-Ionen, des Molekulargewichts des Polymerliganden, der Ionenstärke, der Konzentration an Wasserstoff-Ionen und der Zusammensetzung des Lösungsmittels auf die Polymerisation wurden untersucht. Es wurde geschlossen, daß die Polymerisation nicht nur von der Stabilität des polymeren Chelats sondern auch von seiner Konformation beeinflußt wird. Die Taktizität des erhaltenen Polymethylmethacrylates wurde untersucht.
    Notes: Copper-chelate of polyacrylic hydrazide was prepared, and its structure and properties were investigated. It was found that the chelate-polymer initiates radical polymerization of methyl methacrylate in aqueous dioxane at room temperature. The rate of polymerization initiated by the chelate-polymer was much higher than that by monomeric model-chelate of such as acethydrazide. The catalytic activity found in the copper-chelate of polyacrylic hydrazide is perhaps caused by the polyelectrolyte-behaviour of the polymer. The influences of the concentration of copper ion, molecular weight of polymer-ligand, ionic strength, hydrogen ion concentration and composition of solvent on the polymerization were investigated. It was considered that the polymerization is affected not only by stability but also by conformation of the chelate-polymer. The tacticity of the polymethyl methacrylate obtained is also discussed.
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  • 50
    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: Reaction products of melamine and formaldehyde can be modified by treatment with N -diethyl-trimethylsilyl-amine to yield materials, which are soluble in organic solvents and can easily be fractionated by gel permeation chromatography. Moreover, gel permeation chromatography is used for the quantitative investigation of the course of the sodium-hydroxyde catalysed methylolation of melamine. For this purpose the differential refractometer is calibrated to the corresponding peak area in the chromatograms.In the quantitative determination of the methylolation reaction of melamine in alkaline aqueous solution a difference between the injected and the amount calculated from calibration data was observed. This difference is caused by the presence of polyoxymethylene glycols in the methylolmelamines. Polyoxymethylene glycols are also found in technical melamine-formaldehyde resins.
    Notes: Durch die Umsetzung mit N-Diäthyl-trimethylsilylamin gelingt es, die Melamin-Formaldehyd-Reaktionsprodukte in gelchromatographisch trennbare Stoffe zu überführen. Dadurch kann die Bildung der Methylolmelamine quantitativ verfolgt werden. Hierzu ist die Kalibrierung eines Differentialrefraktometers für alle sechs Methylolmelamine notwending, da jede dieser Verbindungen einen anderen Brechungsindex und damit auch eine andere Abhängigkeit der Peak-Fläche im Elutionsdiagramm von der Substanz-Menge hat.Bei der quantitativen Bestimmung der Methylolierung von Melamin mit Formaldehyd im alkalischem Medium in Molverhältnissen von 1:1 bis 1:6 wurde ein Fehlbetrag zwischen der aufgegebenen und der berechneten Menge festgestellt. Diese Differenz beruht auf der Anwesenheit von Polyoxymethylenglykolen in den Methylolmelamingemischen. Polyoxymethylenglykole wurden auch in technischen Melamin-Formaldehyd-Harzen nachgewiesen.Durch die gelchromatographischen Untersuchungen wurde festgestellt, daß schon im Anfangsstadium der alkalischen Reaktion zwischen Melamin und Formaldehyd neben der Methylolbildung auch im geringen Maße die weitere Kondensation der Methylolmelamine stattfindet.
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  • 51
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 35 (1974), S. 147-157 
    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: Auf der Basis von Hostalit H-9970 (Hoechst AG) hergestellte schlagfeste Polymeren-Systeme wurden durch dielektrische Depolarisationsspektroskopie untersucht. Die in Abhängigkeit von der Temperatur aufgenommenen Depolarisationsspektren wurden mit den dynamisch mechanischen und dielektrischen Relaxationsspektren und mit thermomechanischen Kurven verglichen. Ein enger Zusammenhang wurde zwischen den dielektrischen Depolarisationsmaxima und den durch die mechanische und dielektrische Spektroskopie gemessenen Strukturumwandlungen beobachtet.
    Notes: Toughened PVC systems prepared on the basis of Hostalit H-9970 (Hoechst AG) were studied by dielectric depolarization spectroscopy. The spectra obtained as a function of the temperature were compared with dynamic mechanical and dielectric relaxation spectra and with thermomechanical curves. The dielectric depolarization peaks were found to correlate with the structural transitions measured by mechanical and dielectric spectroscopy.
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  • 52
    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: Silica with covalent bound amino-phenyl groups on its surface is used as initiating agent for the polymerization of N-carboxy-α-amino-acid anhydrides (NCAs). The polymerization rate of the amino-phenyl silica initiated polymerization is about three times faster than the polymerization rate of the polymerization initiated by the comparable low molecular compound p-toluidine (propagation rate constant for the polymerization of L-leucine NCA initiated by amino-phenyl silica in dioxane at 15°C: k = 1,8 · 10-2 1 · mol-1 · sec-1). Both reactions show similar conversion-time curves, which are determined by the slow initiation step. By the reaction of amino-phenyl silica with NCAs, silica polypeptides are obtained with an unextractable polymer content from 20 to 85%, while by adsorption only a little amount of polypeptide (about 5%) is irreversibly bound to the silica surface. With a good solvent, the graft polymer is separable into a soluble and an insoluble silica-polypeptide, but not into silica and polypeptide. These facts and the reaction mechanism indicate a covalent bond between silica and polypeptide.
    Notes: Siliciumdioxid, auf dessen Oberfläche Aminophenylgruppen kovalent gebunden sind, wird als Initiator für die Polymerisation von N-Carboxy-α-aminosäureanhydriden (NCAs) verwendet. Diese Polymerisationen haben den gleichen, durch die langsame Startreaktion bedingten Reaktionsverlauf wie die Polymerisation mit dem vergleichbaren niedermolekularen Initiator p-Toluidin, jedoch laufen sie auf der Siliciumdioxidoberfläche etwa zweibis dreimal schneller ab. (Geschwindigkeitskonstante für die Polymerisation von L-Leucin-NCA mit Aminophenyl-SiO2 in Dioxan bei 15° C: k = 1,8·10-2 1·mol-1 ·sec-1).Die durch Extraktion des Reaktionsprodukts erhaltenen löslichen und unlöslichen SiO2-Polyamide, von denen das Polyamid durch Extraktion nicht abgetrennt werden kann, sowie ein Adsorptionsversuch, bei dem auf der SiO2-Oberfläche wesentlich weniger Polyamid irreversibel gebunden wird als durch die Polyreaktionen auf der Oberfläche, weisen auf eine kovalente Bindung zwischen SiO2 und Polyamid him.
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  • 53
    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: Aus Mischungen wäßriger Dispersionen von hochabriebfestem öl-Ruß (HAF) und Styrol-Butadien-Kautschuk-Latex (SBR) wurden durch Sprühtrocknung Ruß/Elastomer-Pulver hergestellt. Das Verhältnis von HAF/SBR wurde zu 100/0, 95/5, 75/25, 67/33, 50/50, 33/67 und 0/100 Gewichtsteilen gewählt. Die Pulver wurden in einer Kolben/Zylinder-Apparatur Drücken bis zu 19 kbar unterworfen.Unter dem Einfluß des Druckes bildeten sich kompakte Prüfkörper, deren Dichte bei verschiedenen Drücken bestimmt wurde. Unter bestimmten Bedingungen sind diese Prüfkörper porös; der Grad ihrer Porosität wurde sowohl aus ihrer Dichte berechnet als auch aus der Methanolaufnahme experimentell ermittelt.Bei höheren Rußgehalten werden die Prüfkörper zunehmend poröser, wobei ihre Dichte entsprechend abnimmt. Aus Dichtemessungen an dem 3-Phasen-System HAF/SBR/Poren wurde die Dichte des HAF-Rußes bei 19 kbar zu 1,97 g/cm3 bestimmt.
    Notes: Carbon-black/elastomer powders were prepared by spray-drying mixtures of aqueous dispersions of high abrasion furnace (HAF) black with styrene-butadiene rubber (SBR) latex. The HAF/SBR ratio was varied in the range 100/0, 95/5, 75/25, 67/33, 50/50, 33/67 and 0/100 parts by weight. The powders were subjected to pressures up to 19 kbar in a piston-cylinder apparatus.The density of the powders was measured at different pressures and it was found that an interaction between carbon-black and polymer occurs which results in the formation of coherent samples. They exhibit a pressure dependent degree of porosity the magnitude of which was calculated from their density and compared to the porosity determined experimentally from the methanol uptake of the samples.At higher carbon-black loadings the specimen become increasingly porous with a corresponding decrease in density. Density measurements on the three-phase system (HAF/SBR/pores) permitted to determine the density of the HAF-black at 19 kbar as 1.97 g/cm3.Density and porosity at 0 kbar of the pressed specimen are a function of the pressure at which they were prepared. The density increases with increasing pressure whereas the porosity decreases due to stronger interaction between carbon-black and elastomer.
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  • 54
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 35 (1974), S. 169-176 
    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: The predicted (with the help of a mathematical model based on kinetic data) and experimentally found quality of butyl glycidyl ether was compared for various mole ratios of epichlorohydrine to butanol. The extent of polyaddition of epichlorohydrin is apparently lower than hitherto believed.
    Notes: Es wurde die (mit Hilfe eines mathematischen Modells auf Grund kinetischer Messungen) vorausgesagte und experimentell erzielte Qualität eines Butylglycidyläthers bei verschiedenen Ausgangs-Molverhältnissen von Epichlorhydrin zu Butylalkohol verglichen. Die Polyaddition des Epichlorhydrins kommt offensichtlich weniger zur Geltung, als dies aus den bisherigen kinetischen Ergebnissen hervorgeht.
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  • 55
    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: A non-Newtonian flow relation for viscoelastic material was deduced on thermodynamical basis with special respect to the rubber elasticity theory. In this relation the shearing rate appears as a two power function for higher shearing stresses, e.g. technical ones, and is at all characterised by elastic and pure friction properties. This result is in exact coincidence with an earlier flow relation which had been derived from dimensional analysis, and which is also in good agreement with experimental experience.
    Notes: Für das nicht-Newtonsche Fließverhalten viskoelastischer Stoffe wird auf thermodynamischer Basis unter unmittelbarem Anschluß an die Gummielastizitätstheorie eine Fließ-beziehung abgeleitet. Hiernach erscheint die Schergeschwindigkeit bei höheren - etwa technischen-Schubspannungen als quadratische Funktion der letzteren sowie gleichzeitig bestimmt durch die elastischen und reinen Reibungseigenschaften. Das Ergebnis ist in völligem Einklang mit einer bereits früher auf dimensionsanalytischem Wege hergeleiteten Fließbeziehung und wird durch die experimentelle Erfahrung bestätigt.
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  • 56
    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: Wollfasern wurden mit Methylacrylat, äthylacrylat, n-Butylacrylat und Methylmethacrylat zu verschiedenen Pfropfungsgraden unter Stickstoffatmosphäre gepfropft, wobei Cer-ammoniumnitrat in Salpetersäure als Initiator diente. Der Einfluß von Initiator-, Säure-, Monomerkonzentration, Temperatur und Pfropfungsdauer wurde untersucht. Es ergab sich die folgende Reaktivitätsreihe der Monomeren: Methylacrylat 〉 äthylacrylat 〉 Methylmethacrylat 〉 n-Butylacrylat. Die Molekulargewichte der Pfröpflinge wurden bestimmt.
    Notes: Wool fibres were grafted with methyl acrylate, ethyl acrylate, n-butyl acrylate and methylmethacrylate to various percentages of grafting in nitrogen atmosphere using ceric ammonium nitrate in nitric acid as initiator. The effects of concentration of the initiator, acid, monomer, temperature and time on the grafting were investigated. A comparison of such results indicated the following reactivity order of monomers: methyl acrylate 〉 ethyl acrylate 〉 methylmethacrylate 〉 n-butyl acrylate. The molecular weights of the grafts were investigated by isolating the grafts from the fibres.
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  • 57
    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: The fractionation of homo- and copolymers by GPC-experiments was investigated, using surface modified silica gels as porous supports. Linear polystyrenes, poly-α-methyl-styrenes, and polybutadienes have been analysed.Methods are shown which consider the hydrodynamic broadening effects due to GPC. A computer program of PROVDER and ROSEN has been improved by a subsequentiteration method. With this program good results for molecular weightdistributionscould be obtained.“True” molecular weight averages and polydispersities have been measured with a recycle method of WATERS and with extrapolation by HAMIELEC.By comparison with results from sedimentation transport runs and ϑ-fractionations a good agreement has been achieved within the limits of error of these methods.The (α-methyl styrene methacrylonitrile)-copolymers have been analysed fortheir heter-ogeneity of chemical composition. These polymers show an unusual elution behaviour,and exhibit more chemical heterogeneity than is computed by kinetic data.
    Notes: In dieser Arbeit werden gelchromatographische Trennungen an oberflächenmodifizierten Silikagelen durchgeführt, die sich sehr gut zur Fraktionierung von Homo- und Copolymeren eignen. Untersucht werden lineare Polystyrole, Poly-α-methylstyrole und Polybutadiene, ebenso wie radikalisch polymerisierte α-Methylstyrol-Methacrylnitril-Co-polymere.Es werden Methoden aufgezeigt, die die hydrodynamischen Verbreiterungseffekte bei der Gelpermeationschromatographie berücksichtigen. Ein schon von PROVDER und ROSEN beschriebenes Rechenverfahren wird durch eine anschließende Nachiteration verbesert. Hiermit sind dann befriedigende Korrekturen für die Molekulargewichtsverteilung möglich.Mit einer bereits von WATERS vorgeschlagenen Zirkulationsmethode und einem Extra polationsverfahren von HAMIELEC werden die „wahren“ Molekulargewichtsmittelwerte und Uneinheitlichkeiten berechnet.Vergleiche mit Daten aus Sedimentationstransportläufen und Lösefraktionierungen im ϑ-System ergeben im Rahmen der Fehlergrenzen dieser Methoden befriedigende überinstimmung.Die α-Methylstyrol-Methacrylnitril-Copolymeren werden hinsichtlich der Heterogenität ihres chemischen Aufbaus untersucht. Diese Copolymeren zeigen ein eigenartiges Elutionsverhalten und weisen mehr chemische Hetrogenität auf, als den Rechnungen mittels kinetischer Daten entspricht.
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  • 58
    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: The influence of concentration and the conditions of preparations of fiber-forming solutions, containing a mixture of polyacrylonitrile-polymethyl methacrylate in dimethyl-formamide upon the rheological behaviour of the solutions and the rupture length of the films obtained thereof, have been investigated. The method of the “experimental design” was employed for this purpose.It was established that the obtained flow curves are satisfactorily described by the Ostwald model τ = K·γη. Regression equations were deduced concerning the influence of the total concentration of the solution, of polymethyl methacrylate in the solution, the agitation time, the speed of stirrer revolution, and the dissolution temperature upon the rheological coefficients K and n and the rupture length of the films. There follows from the analysis of these equations that the governing parameters may be chosen in such a way that K and n decrease, without markedly decreasing the rupture length.
    Notes: Der Einfluß der Konzentration und der Bedingungen bei Gewinnung von faserbildenden Lösungen aus Polyacrylnitril-Polyacrylnitril-Polymethylmethacrylat-Gemischen in Dimethylformamid auf das rheologische Verhalten der Lösungen und der Reißlänge der daraus erhaltenen Filme wurde untersucht. Für diesen Zweck wurde die Methode der „Versuchsplanung“ angewandt.Die Bließkurven wurden befriedigend durch das Modell von Ostwald τ = K·γη beschrie-ben. Is wurden Regressionsgleichungen für den Einfluß der Gesamtkonzentration der Lösung, der Konzentration des Polymethylmethacrylats in der Lösung, der Rührzeit und der Umdrehungszahl des Rührers und der Lösungstemperatur auf die rheologischen Koeffizienten K und n und auf die Reißlänge der Filme ermittelt. Es folgte aus der Analyse der Gleichungen, daß die Steuerparameter so gewählt werden können, daß K und n kleiner werden, ohne daß dabei die Reißlängen empfindlich vermindert werden.
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  • 59
    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: Durch Sprühtrocknung von Mischungen wäßriger Dispersionen von hochabriebfestem Ölruß (HAF) und Butadien-Styrol-Kautschuklatex (SBR) wurden Pulvermischungen im gesamten Mischungsbereich von 0 bis 100% SBR hergestellt.Durch Einwirkung von statischem Druck bis zu 19 kbar auf diese HAF/SBR-Pulver bildeten sich bei Raumtemperatur kompakte Prüfkörper, die sich in manchen Eigenschaften wie HAF/SBR-Vulkanisate verhielten.Das Modul/Druck-, Modul/Temperatur-, Quellungs- und Löslichkeitsverhalten dieser Systeme wurde untersucht. Der Torsionsmodul, der zwischen -100 und +150°C gemessen wurde, zeigte einen Anstieg über mehrere Zehnerpotenzen mit steigendem Rußgehalt. Die scheinbare Vernetzungsdichte des Polymeren in dem gepreßten HAF/SBR Prüfkörper wurde aus der Gleichgewichtsquellung in Toluol ermittelt. Es wurde gefunden, daß die scheinbare Vernetzungsdichte sowohl mit steigendem Rußgehalt als auch mit steigendem Herstellungsdruck der Proben ansteigt.Die Anwendung einer Theorie von Vergnon über die Druckabhängigkeit des Kompressionsmoduls von Metallpulvern auf HAF-Ruß gestattete die Berechnung der Dichte des HAF-Rubes unter optimalen Packungsbedingungen zu 2,00 g/cm3.
    Notes: Powders from HAF-black/SBR mixtures in the total range of composition from 0 to 100% SBR were prepared by spray-drying mixtures of aqueous dispersions of HAF-black and SBR.Application of static pressure up to 19 kbar to these HAF-black/SBR powders at room temperature yielded coherent specimens which in many respects behaved like vulcanized HAF/SBR compounds.The modulus-pressure, modulus-temperature, swelling and solubility behaviour of these systems was studied. The torsional modulus which was measured between -100 and +150 C showed an increase over several decades with increasing carbon-black content. From the equilibrium swelling in toluene the apparent crosslink density of the polymer in the pressed HAF/SBR specimen was estimated. It was found that the apparent crosslink density increases with increasing carbon-black content and also with the pressure at which the samples were prepared.The application of Vergnon's theory about the pressure dependence of the bulk modulus of metal powders to HAF-black permitted to calculate the density of HAF-black at ideal packing conditions as 2.00 g/cm3.
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  • 60
    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: Die photoinduzierte Polymerisation von Acrylnitril und Acrylamid wurde in wäBriger Lösung in Gegenwart vom System Fe(III)salz und Saccharid untersucht. Es ergab sich, daß der Effekt der verschiedenen Fe(III)salze auf die Polymerisationsgeschwindigkeit folgende Reihe hat: Fe(III)-nitrat, -perchlorat und -chlorid 〉 Fe(III)-ammoniumsulfat 〉 Kaliumferricyanid. Dagegen war der Effekt von neutralen Salzen wie Natriumnitrat, -chlorid und -perchlorat auf die Polymerisationsgeschwindigkeit vernachlässigbar. Die maximale Geschwindigkeit wurde im pH-Bereich von 2 bis 3 erreicht, und die spektropho-tometrisch bestimmte Geschwindigkeit des Fe(III)ionenverbrauchs zeigte ein Maximum im gleichen pH-Bereich. Aus den Ergebnissen wurde die Auslösungsspezies der in Frage kommenden Photopolymerisation diskutiert.
    Notes: Photoinduced polymerization of acrylonitrile and acrylamide in the presence of Fe(III) salt and saccharide was studied in aqueous solution. The effect of various Fe(III) salts on the rate of polymerization was found to be in the following order: Fe(III) nitrate, perchlorate and chloride 〉 Fe(III) ammonium sulfate 〉 potassium ferricyanide. On the other hand, the effect of neutral salts such as sodium nitrate, chloride and perchlorate on the rate of polymerization was negligibly small. The maximal rate of the photopolymerization attained at the pH region of about 2 to 3, and the rate of Fe(III) ion consumption determined spectrophotometrically revealed also a maximum in the same pH region. From these results, initiating species of the photopolymerization was discussed.
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  • 61
    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: Der Effekt von Farbstoffen auf den Spannungsrelaxationsmodul von Polyacrylnitril und Polyamid wurde untersucht. p-Aminobiphenyl als Modellverbindung für Dispersionsfarbstoffe senkt die Glasumwandlungstemperatur von Polyacrylnitril zusätzlich zu der durch Wasser verursachten Erniedrigung. Andere nichtionische Verbindungen bewirken den gleichen Effekt. Dagegen beeinflußt Malachitgrün den Spannungsrelaxationsmodul nicht. Die Mechanismen der Plastizierung durch Farbstoffmoleküle und die Konzentrationsabhängigkeit des Diffusionskoeffizienten werden diskutiert.
    Notes: The effect of dye on the stress relaxation modulus of poly(acrylonitrile) and polyamide was determined. p-Aminobiphenyl as a model compound for dispersed dyes depresses the glass transition temperature of poly(acrylonitrile) in addition to the depression caused by water. Other non-ionic diffusants were examined and produce a similar effect. In contrast, malachite green has no effect on the stress relaxation modulus. The mechanism of plasticization by dye molecules and the concentration dependence of the diffusion coefficient is discussed.
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  • 62
    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: Solution properties of polyoctenamers were studied. A relation [η]-M in toluene at 25°C was elucidated. The kθ-value derived from this relation agrees quite well with similar data of polybutadiene, polypentenamer and polyethylene. No evidence was found for the existence of cyclic structures in polyoctenamers.
    Notes: Lösungseigenschaften von Polyoctenameren wurden untersucht. Eine Viskositäts-Molekulargewichts-Beziehung in Toluol bei 25°C wurde ermittelt. Der daraus abgeleitete kθ-Wert stimmt mit den für Polybutadien, und Polyäthylen bekannten Werten überein. Ein Hinweis auf die Existenz von ringförmigen Makromolekülen konnte nicht gefunden werden.
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  • 63
    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: At room temperature water and organic mono- and polyhydroxyl compounds form - particularly with 5- to 7-membered lactams - associates of strikingly low viscosity. The present paper is concerned with significant aspects of the properties and practical applica-tions of these c-caprolactam associates. 6-caprolactam/water associates are of interest as solvents for materials which are difficult to dissolve, contain water or polyols rcsp. bound in activated form for reaction with isocyanates and exhibit interesting propertics as chain-lengthening and blowing agents in foaming processes. Because of their remarkable properties the associates may be considered as low-molecular weight cyclic structures with hydrogen bonding. Mono- and polyhydroxyl compounds and oximes are also highly activated by forming associates with 6-caprolactam and, being liquid systems completely free of solvent, they can be used in a wide variety of ways as structural elements in isocyanate chemistry which allow non-polluting techniques. 8:-Caprolactam associates can be employed for linearization of polyurethanes and polyurethane polyureas crosslinked by biuret and allophanate groups. Partial or quantitative linearization with elimination of biuret and allophanate crosslinking sites in foams yields new types of matrices similar to textiles with extremely reduced deflection hardness. The heavy swelling which takes place in linearized cellular polyurethane matrices is utilized for inducing matrix reactions and the cellular structure in the spaces newly created by the swelling pressure and the irreversible fixation of the swelling caused by rapid solids formation of the coreactants results in interesting foam combinations.
    Notes: Wasser und organische Mono- und Polyhydroxylverbindungen bilden insbesondere mit 5- bis 7gliedrigen Lactamen bei Raumtemperatur auffallend dünnviskose Assoziate. Eigenschaften und Nutzanwendungen der ε-Caprolactam-Assoziate in der Isocyanat-Chemie werden in der vorliegeden Arbeit schwerpunktsmäßig behandelt. ∊-Caprolactam-Wasser-Assoziate sind interessante Lösungsmittel für schwerlösliche Stoffe, enthalten Wasser bzw. Polyole in gegenüber Isocyanaten aktivierter Form gebunden und weisen bei Verschäumungsprozessen interessante Eigenschaften als Kettenverlängerungsmittel und Treibmittel auf. Auf Grund auffallender Eigenschaften der Assoziate werden diesen niedermolekulare, cyclische Strukturen unter Ausbildung von Wasserstoffbrückenbindungen zugeordnet. Auch Mono- und Polyhydroxylverbindungen sowie Oxime werden durch Assoziat-Bildung mit ∊-Caprolactam stark aktiviert und lassen sich als flüssige, völlig lösungsmittelfreie Systeme in umweltfreundlichen Verfahren in vielfältiger Weise als Baukomponenten in der Isocyanatchemie verwenden. ∊-Caprolactam-Assoziate können zur Linearisierung von über Biuret- und Allophanat-Gruppen vernetzten Polyurethanen und Polyurethanpolyharnstoffen herangezogen werden. Die partielle oder quantitative Linearisierung unter Eliminierung von Biuret- und Allophanatvernetzungsstellen in Schaumstoffen führt zu neuartigen, textilartigen Matrizen mit extrem verminderter Stauchhärte. Die starken Quellungsvorgänge an linearisierten cellulären Polyurethanmatrizen werden zur Durchführung von Matrizen-Reaktionen ausgenutzt, wobei die zellförmige Stoffanordnung in den durch den Quellungsduruck neu erzeugten Räumen und die irreversible Fixierung des Quellungszustandes durch rasch verlaufende Feststoffbildung der verwendeten Reaktionspartner zu interessanten Kombinationsschaumstoffen führt.
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  • 64
    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: On crosslinking of some unsaturated polyesters by electron beams more than 60% of the unsaturated basic units react. A dimerisation is by far the dominating reaction. Oligomers are formed only in very small amounts. The modulus of elasticity, the tensile strength and the elongation at break of films obtained from unsaturated polyesters by electron beam curing were higher than those of unsaturated polyester resins containing styrene, either cured by peroxide or by electron beams.
    Notes: Bei der Vernetzung der untersuchten ungesättigten Polyester durch Elektronenbestrahlung reagieren über 60% der ungesättigten Grundeinheiten. Dabei findet in weit überwiegendem Maße eine Dimerisierung statt. Oligomere werden nur in ganz geringem Umfang gebildet. Filme, die durch Elektronenbestrahlung ungesättigter Polyester erhalten wurden, zeigten einen höheren E-Modul, höhere Zerrißfestgkeit und auch eine höhere Bruchdehnung als peroxidisch oder durch Elektronenstrahlen gehärtete ungesättigte Polyesterharze mit Styrol als Comonomerem.
    Additional Material: 6 Ill.
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  • 65
    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: Self-diffusion of benzene and polystyrene in the system benzene-polystyrene is studied by means of spin-echo-technique as function of temperature, concentration and polymer molecular weight. From the dependence of temperature the activation energies are calculated as function of concentration and molecular weight. The concentration dependence is discussed in terms of restricted diffusion and the Fujita Free-Volume-Theory. The computed free volume shows a significant maximum at 50°C. This effect may be attributed to a change in the mobility of the phenyl side groups of polystyrene and is vanishing with decreasing molecular weight. The free-volume-temperature curves are giving references to the glass transition.
    Notes: Die Selbstdiffusion des Benzols und des Polystyrols im System Benzol-Polystyrol wird mit Hilfe der Spin-Echo-Technik in Abhängigkeit von der Temperatur, der Konzentration und dem Molekulargewicht untersucht. Aus der Temperaturabhängigkeit des Selbstdiffusionskoeffizienten werden Aktivierungsenegien als Funktion der Konzentration und des Molekulargewichtes bestimmt. Die Konzentrationsabhängigkeit wird aufgrund der Vorstellungen über die behinderte Diffusion und in Anlehnung an die Theorie des Freien Volumens nach Fujita diskutiert. Das berechnete Freie Volumen zeigt bei ungefahr 50°C ein ausgeprägtes Maximum, das sich mit abnehmendem Molekulargewicht abschwächt. Die beobachtete Zunahme des Freien Volumens kann auf Änderungen in der Beweglichkeit der Phenylseitengruppen zurückgeführt werden. Die Temperaturabhängigkeit des Freien Volumens zeigt Hinweise auf den Glasübergang.
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  • 66
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 37 (1974), S. 135-140 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wird gezeigt, daß die paramagnetische Sondenmethode bei Untersuchungen von Polymer-Weichmacher-Wechselwirkungen verwendbar ist. Mit dieser Methode wurde gefunden, daß die Relaxationszeit der Rotation der Sondenradikale im weichgemachten PVC bei Erhöhung der Menge des Weichmachers erheblich verkleinert wird. Zwischen der Relaxationszeit τ und dem Youngschen Elastizitätsmodul G besteht eine lineare Korrelation, welche auf eine starke Einwirkung der Mikroeigenschaften auf die mechanischen Eigenschaften des Gels hinweist. Die Translationsdiffusionskonstanten der Weichmachermoleküle liegen bei Zimmertemperatur im Bereich von 0.2×10-8cm2/s bis 4.6×10-8cm2/s, was auf eine ziemlich freie Beweglichkeit der Weichmachermoleküle im PVC-Gel hindeutet.
    Notes: The spin probe technique is suggested to be suitable for the study of polymer-plasticizer interactions. In this work it was found that the rotational relaxation time (τ) of probe radicals in plasticized poly(vinyl chloride) (PVC) diminishes strongly when the amount of plasticizer is increased. A linear correlation between τ and Young's modulus (G) was observed. This indicated that the microstate considerably influences the mechanical behaviour of the gel. The translational diffusion constant of plasticizer molecules at 25°C was calculated to change from 0.2 times; 10-8 cm2/s (PVC weight fraction 0.83) to 4.6 times; 10-8 cm2/s, (PVC weight fraction 0.20). These values indicate a high degree of freedom for lateral motion of plasticizer molecules in gels.
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