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  • Articles: DFG German National Licenses  (9)
  • 1995-1999  (6)
  • 1990-1994
  • 1980-1984
  • 1960-1964  (3)
  • 1955-1959
  • 1930-1934
  • 1890-1899
  • 1999  (6)
  • 1963  (3)
  • 1959
  • Polymerization
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  • Articles: DFG German National Licenses  (9)
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Years
  • 1995-1999  (6)
  • 1990-1994
  • 1980-1984
  • 1960-1964  (3)
  • 1955-1959
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Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Effect of protein concentration on whey protein gels obtained by a two-stage heating process (1999)
    Springer
    European food research and technology 209 (1999), S. 389-392 
    Details
    ISSN: 1438-2385
    Keywords: Key words Gelation ; Polymerization ; Whey proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  The influence of protein concentration on the properties of gels obtained by a two-stage heating process was determined. In the first stage, whey protein dispersion (3–10%) was heated at pH 8.0, and in the second stage it was diluted to 3% protein, adjusted to pH 7.0 and heated again. Increased protein concentration in the first stage of polymerization resulted in the gels obtained in the second stage having a lower phase angle, increased storage modulus and increased hardness. Increased protein concentration also resulted in gels with an increased optical density, which suggests thathigher protein concentration leads to more and larger aggregates. Gels obtained from dispersions preheated at a higher protein concentration had higher permeability coefficient (B gel) values. The increase in B gel suggests that the higher protein concentration increased the size of the aggregates, which in a second stage of heating formed a gel matrix with a larger pore size.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002170050514
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Ab initio MO study of ethylene insertion into the Sm–C bond of H2SiCp2SmCH3 (1999)
    Springer
    Theoretical chemistry accounts 102 (1999), S. 285-292 
    Details
    ISSN: 1432-2234
    Keywords: Key words: Ethylene insertion ; ab initio MO calculations ; Sm complexes ; Polymerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract. Ethylene insertion into the Sm–C bond of H2SiCp2SmCH3, a model reaction of an olefin polymerization propagation step, has been studied by ab initio molecular orbital methods. The small electronegativity of the Sm atom makes the Sm–C bond ionic, the methyl group being negatively charged by −0.75. The reaction passes through a loose ethylene complex with a binding energy of 15 kcal/mol and then a tight four-centered transition state with an agostic interaction between the Sm atom and one of the methyl CH bonds. A small activation energy of 14 kcal/mol is required to pass through this transition state, indicating that this is an easy reaction. Compared with the reactions with group 4 cationic silylene-bridged metallocenes the activation energy is higher and the reaction is less exothermic. The origin of these differences is discussed. The results of molecular mechanics calculations on regio- and stereoselectivities in the insertion reaction of propylene are also reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002140050500
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Improvement of dispersing property of sodium sulfite-formal-dehydeanthraquinone pulping effluent by treatment withCoriolus versicolor (1999)
    Springer
    Journal of wood science 45 (1999), S. 143-148 
    Details
    ISSN: 1611-4663
    Keywords: Coriolus versicolor ; Na2SO3-HCHO-AQ pulping effluent ; Polymerization ; Lignosulfonate ; Laccase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A strain of the fungusCoriolus versicolor was inoculated periodically into potato dextrose agar (PDA) slants containing the effluent to enhance the natural ability to grow in the effluent. The acclimated strain grown in the 50% effluent-containing PDA slant and the original strain were employed to treat the effluent. The acclimated strain could grow in a higher concentration of the effluent than the original unacclimated one. Both the original and acclimated strains improved the dispersing ability of the effluent, especially the acclimated strain because of its higher laccase secretion. The dispersing ability of the SFP effluent was improved to a level comparable to a commercial lignosulfonate product because it was strongly polymerized by the fungus. During the fungal treatment, more than 50% of the sugars were removed from the effluent, thereby increasing the purity of the SFP lignin product.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01192331
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Kinetic study of the formation reaction of colloidal silica spheres in microgravity using aircraft (1999)
    Springer
    Colloid & polymer science 277 (1999), S. 474-478 
    Details
    ISSN: 1435-1536
    Keywords: Key words Reaction kinetics in microgravity ; Colloidal silica spheres ; Polymerization ; Transmitted-light intensity ; Dynamic light scattering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Polymerization reactions of colloidal silica spheres via the hydrolysis and dehydration processes of tetraethyl orthosilicate with ammonia and a tiny amount of water in ethyl alcohol have been studied in microgravity by the parabolic flights of a MU-300 rear-jet aircraft. Induction periods and polymerization rates are determined by fast-scanning transmitted-light-intensity measurements and the fast-scanning dynamic light-scattering method. Direct observation of the reaction mixtures is also made with a charge-coupled device video camera. Reproducible and reliable data are obtained in microgravity compared with those in gravity. Increases in the induction times and decreases in the polymerization rates are observed in microgravity compared with those in gravity. One of the main reasons for these observations is the fact that the translational Brownian movement of the reactants and/or product spheres is free from downward translational movement in microgravity. Very weak convection of the reaction suspensions in microgravity is another important factor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003960050411
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Polymerization of aqueous liquid-crystalline allyldimethyldodecylammonium bromide (1999)
    Springer
    Colloid & polymer science 277 (1999), S. 1215-1219 
    Details
    ISSN: 1435-1536
    Keywords: Key words Allyldimethyldodecylammonium bromide ; Liquid crystals ; Polymerization ; Polymerizable surfactant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Allyldimethyldodecylammonium bromide was polymerized by γ-ray irradiation in both hexagonal and cubic mesophases, and the conversion–time curves were obtained. The maximum conversion was about 35%, and the polymer remained in the liquid-crystalline structure formed by the nonpolymerized monomers. The influence of polymerization on the distribution of water in the different types related to the hydrophilic surfaces of microstructures was studied using Fourier transform infrared spectroscopy. The incomplete polymerization was explained by steric constraints in the liquid-crystalline structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003960050513
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Polymerization of vinyl acetate in homogeneous systems obtained in presence of acrylic acid (1999)
    Springer
    Colloid & polymer science 277 (1999), S. 203-209 
    Details
    ISSN: 1435-1536
    Keywords: Key words Microemulsions ; Vinylacetate ; Acrylic acid structure ; Polymerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The composition ranges over which microemulsions are formed in systems containing vinyl acetate, acrylic acid, water with nonylphenol ethoxylated with 25 mol ethylene oxide monomaleate as surfactant were studied. Conductometric and refractometric investigations have shown the existence of some aqueous/organic, bicontinuous and organic/aqueous microemulsions. The types of precursor microemulsions influence the conversion of monomers. In the presence of a crosslinking agent, diethylene glycol bis maleate, hydrogels are formed whose water absorption depends on the composition of the initial microemulsions. The kinetics of water absorption suggests the modification of polymer network structures as a function of the crosslinked monomer content and the ratio of organic to aqueous phases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00013744
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  • 7
    Electronic Resource
    Electronic Resource
    Low-Temperature Polymerization of EthylenePublished on the occasion of the 100th anniversary of the founding of Farbwerke Hoechst on January 11th, 1963 (1963)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 32-41 
    Details
    ISSN: 0570-0833
    Keywords: Polymerization ; Polyethylene ; Titanium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A two-component organometallic catalyst of composition CH3TiCl3·CH3AlCl2 effects high-speed polymerization of ethylene in the presence of chlorinated hydrocarbons at low temperatures. The catalyst does not undergo any alteration in the process. In contrast to the Ziegler catalysts, the titanium remains quadrivalent. Olefins of low-molecular-weight and with branched structures are produced. It proved possible to isolate the primary products of the polymerization at -50 to -100°C and to elucidate the mode of their formation from a knowledge of their structures. The findings are incompatible with either a cationic or anionic reaction mechanism. A novel type of mechanism is proposed, whereby the catalyst is supposed to have an ionic structure and molecular growth proceeds via π-complex formation of the olefin with the titanium cation. The formation of ethylene/olefin copolymers is also discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196300321
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    Paper (German National Licenses)
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  • 8
    Electronic Resource
    Electronic Resource
    Emulsion Polymerization of Vinyl Monomers under the Influence of Ionizing Radiation (1963)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 295-308 
    Details
    ISSN: 0570-0833
    Keywords: Emulsion polymerization ; Polymerization ; Polymerization ; Alkenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ionizing radiation induces the polymerization of some vinyl monomers in aqueous emulsion with high radiation yields. With identical emulsion compositions, the kinetics of this reaction and the kinetics of emulsion polymerization induced by water-soluble initiators are very similar. The rate of reaction in emulsion polymerization is about one hundred times greater than in bulk polymerization. The initiation of emulsion polymerization by means of ionizing radiation permits uniform “illumination” of the reacting volume, as well as almost any desired variation in the frequency of initiation during the reaction. The sharp decrease in the overall rate of reaction when initiation is interrupted during emulsion polymerization of styrene induced by γ-rays contradicts the earlier concept of sharply separated reaction zones.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196302951
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  • 9
    Electronic Resource
    Electronic Resource
    Reactions of Olefins with the Titanium-Carbon BondDedicated to Prof. Dr. Karl Ziegler on the occasion of his 65th birthday (1963)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 704-714 
    Details
    ISSN: 0570-0833
    Keywords: Titanium ; Alkenes ; Polymerization ; Titanium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: At low temperatures, ethylene and α-olefins (Δ1-olefins or 1-alkenes) are rapidly converted into oligomrs by the two-component organometallic catalyst CH3TiCl3·CH3AlCl2. To achieve smooth oligomerizations, aromatic or chlorinated hydrocarbons must be used as solvents. Although the activity of the titanium-carbon bond is enhanced by the aluminum component of the catalyst, the aluminum and its methyl group do not participate in the reaction proper; the latter proceeds exclusively at the titanium-carbon bond. The reaction will olefins can be used as an analytical method for the quantitative determination of the titanium-carbon bond in admixture with the organoaluminum component. It is thus possible to follow the reaction leading to formation of the catalyst from titanium tertrachloride, as well as the processes occurring at the titanium-carbon bond during the oligomerization of olefins. All the observations indicate that the catalyst possesses an ionic structure which is determined by the solvent. It is shown that the initial reaction step probably involves formation of a complex between the olefin and the alkyltitanium cation. The reaction scheme proposed is based on organometallic reactions which are characterized by carbanion and hydride transfers within the olefin-cation complex. This mechanism, which is unusual for Ziegler catalysts, is due to the predominance of hydride transfers.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196307041
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    Paper (German National Licenses)
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