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  • 2020-2022
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  • 1860-1869
  • 1850-1859
  • Polymerization
  • 1
    Electronic Resource
    Electronic Resource
    Influence of a high-speed polymerization method on the marginal integrity of composite fillings in class-II cavities (2000)
    Springer
    Clinical oral investigations 4 (2000), S. 42-49 
    Details
    ISSN: 1436-3771
    Keywords: Key words Composite resins ; Polymerization ; Marginal adaptation ; Light intensity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The aim of this study was to evaluate the effect of a rapid photopolymerization method on the marginal integrity of composite fillings. Ninety two-surface cavities were prepared in extracted human molars using the SonicSys preparation system. All cavities were bonded with one bonding agent (Syntac) and filled with a microfilled composite (Herculite XRV), a heavy filled composite (Z100 MP), and an Ormocer (Definite) in two increments. Each increment had a thickness of approximately 1.5 mm and was polymerized using either halogen light or the plasma light of Apollo 95 E. In this process, six trial groups each containing 15 fillings were created. After replicas were made, the test teeth were subjected to a thermocycling process of 2000 temperature cycles (5°C/55°C) followed by a wear simulation of 50,000 stress cycles each with 50 N. This was followed by the creation of a second set of replicas, quantitative margin analysis, and dye penetration. A significant (P〈0.05) influence of the thermomechanical stress and a significant (P〈0.05) influence of the factor ”material” were shown for the margin criterion ”continuous margin” using MANOVA. The factor ”light source” produced no significant influence (P=0.57) on the amount of continuous margin. During the dye penetration, no significant differences between the polymerization methods could be established with the materials Herculite XRV and Z100 MP (H-test according to Kruskall and Wallis). Only with the material Definite was a significantly higher dye penetration observed at the occlusal measuring point in the plasma light group. A rapid polymerization with high light intensity had no adverse effects on the margin quality within the limitations of this in vitro study. However the marginal integrity might have been influenced by the chosen adhesive system/composite resin combination, which does not represent the respective product line. Additionally, further studies ought to show which exposure time is necessary for a sufficient degree of conversion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007840050112
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  • 2
    Electronic Resource
    Electronic Resource
    Radical polymerization and copolymerization behavior of 1-cyanoethanoyl-4-acryloylthiosemicarbzide (2000)
    Springer
    Journal of polymer research 7 (2000), S. 229-235 
    Details
    ISSN: 1572-8935
    Keywords: Functional monomers ; Polymerization ; Copolymerization ; Kinetic studies ; Reactivity ratios
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract 1-Cyanoethanoyl-4-acryloylthiosemicarbazide (CEATS) was synthesized for the first time as a new chelating monomer. Its structure was confirmed by both elemental and spectral analyses. Radical polymerization and copolymerization of CEATS was been carried out in dimethylformamide (DMF) in the presence of azobisisobutyronitrile (AIBN) as an initiator. Kinetic studies for the polymerization behavior of CEATS were performed. The complex formation of the CEATS monomer and polymer (PCEATS) with Cu II cation was investigated and its stability constant determined. The rate of copolymerization of CEATS with some conventional monomers, namely vinyl acetate, methyl methacrylate and acrylonitrile, was measured as a function of the mole fraction of the monomers. The reactivity ratios (r1, r2) for the various copolymer systems investigated together with the Q and e values of the CEATS monomer were determined. Moreover, the thermal gravimetric analysis of the prepared polymers and their copolymers with acrylonitrile were also studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10965-006-0124-x
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  • 3
    Electronic Resource
    Electronic Resource
    Studies on the synthesis and properties of terpene-phenol-aldehyde resin with a high softening point (2000)
    Springer
    Journal of wood science 46 (2000), S. 143-148 
    Details
    ISSN: 1611-4663
    Keywords: α-Pinene ; Phenol ; Formaldehyde ; Polymerization ; Condensation
    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 Synthesis conditions of terpene-phenol-aldehyde resin with a high softening point were studied based on the reactions amongα-pinene, phenol, and formaldehyde. A suitable catalyst system and the best processing conditions were obtained by laboratory experiments. The influence of the raw materials ratios, reaction temperature, reaction time, and catalyst dose on the softening point, yield, and color of the synthesized resin was examined. The physical and chemical characteristics of the resin were determined: softening point ≥140°C (ball and ring method); color value ≤7 (Gardner); acid value (KOH mg/g) 〈1; bromine value (Br2 mg/100g) 〈64; saponification value (KOH mg/g) 〈1; average molecular weight ∼830. The yield of resin was more than 85% (based on the total raw material).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00777361
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of the structures of microemulsions on chemical reactions (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 150-154 
    Details
    ISSN: 1435-1536
    Keywords: Key words Hydrolysis kinetics ; Polymerization ; Microemulsions ; Aspirin ; Styrene
    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 Two kinds of chemical reactions were studied in two different microemulsion systems: cetyltrimethylammonium bromide/1-butanol/10 and 25% n-octane/water and sodium dodecyl sulfonate/1-butanol/20% styrene/water. One reaction is a hydrolysis reaction, in which aspirin and 2,4-dinitrochlorobenzene were used as the hydrolysis substrates. The second reaction is the polymerization of styrene, which was initiated by using two initiators, water-soluble K2S2O8 and oil-soluble 2,2′-azobis(isobutyronitrile), and, at the same time, the polymerization of acrylamide, which was initiated by NaHSO3, was also studied. All the hydrolysis reaction experimental results show that the hydrolysis is greatly affected by the structures and the structural transitions of microemulsions. The hydrolysis rates are higher in water-in-oil (W/O) microemulsion media and decrease with the addition of water. The rates increase in bicontinuous (BC) microemulsions and decrease in oil-in-water (O/W) microemulsions. The transition points of the hydrolysis rates occurred at the two microemulsion structural transition points from W/O to BC and from BC to O/W. The polymerization relationships between the conversions of styrene, the molecular weights of polystyrene and the water contents of the microemulsion system were obtained. The effects of microemulsion structures on the sizes of the polystyrene particles and on the molecular weights of the polymers are discussed. Polystyrene particles with diameters of 10–60 nm were observed by microscopy. Our experimental polymerization results show that microemulsions are suitable as media for the production of polymers, the molecular weights and the particle sizes of which can be controlled and predicted by variations in microemulsion structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003960050025
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  • 5
    Electronic Resource
    Electronic Resource
    Alcoholysis of Aluminum Alkyls Supported by Bulky Phenoxide Ligands: Synthesis, Characterization, and ε-Caprolactone Polymerization Activity of Two Dimeric Aluminum Isopropoxides (2000)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 441-445 
    Details
    ISSN: 1434-1948
    Keywords: Aluminum ; Alkoxides ; Lactone ; Ring-opening ; Polymerization ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of trialkylaluminum Al2R6 (R = Me, Et) with 2,2′-methylenebis(6-tert-butyl-4-methylphenol) (mbmpH2) gives the dimeric mono(alkyl) complex [Al(mbmp)R]2 with bridging oxygen atoms. Reaction of [Al(mbmp)R]2 with one equiv. of 2-propanol results in the formation of the dimeric isopropoxide [Al(mbmp)(μ-OiPr)]2. Single-crystal X-ray analysis shows a C2h-symmetric structure with a planar Al2O2 core. Monomeric methylbis(2,6-di-tert-butyl-4-methylphenolato)aluminum, AlMe(OC6H2-2,6-tBu2-4-Me)2 (MAD), was found to react with one equiv. of 2-propanol to give a dimeric isopropoxide [AlMe(OC6H2-2,6-tBu2-4-Me)(μ-OiPr)]2 in which the bulky phenolate, instead of the methyl group, has been displaced. According to the single-crystal X-ray structure analysis, the molecule contains a similar Al2O2 core, but the two 2,6-di-tert-butyl-4-methylphenolato ligands are cis- and orthogonally arranged to each other. ε-Caprolactone is polymerized at 50 °C in toluene in a controlled manner by [Al(mbmp)(μ-OiPr)]2, to give poly(ε-caprolactone) with high molecular weights and narrow molecular weight distributions (Mw/Mn 〈 1.50). The low efficiency values (number of polymer chains initiated per aluminum atom) imply that [Al(mbmp)(μ-OiPr)]2 exists in a monomer-dimer equilibrium. The polymerization of ε-caprolactone by [AlMe(OC6H2-2,6-tBu2-4-Me)(μ-OiPr)]2 is faster, but somewhat less controlled.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Polymerization of a monomeric guanosine derivative in a hydrogen-bonded aggregate (1989)
    Springer
    Journal of molecular evolution 29 (1989), S. 367-369 
    Details
    ISSN: 1432-1432
    Keywords: Guanosine derivatives ; Self-aggregation ; Amino acids ; Polymerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The adduct IIa, in which glycine is linked to the 3′-amino group of 3′-amino-3′-deoxyguanosine-5′-phosphate, condenses very efficientlyin aqueous solution when treated with a watersoluble carbodiimide to give long oligomeric products. The corresponding cytidine derivative IIb yields a complex mixture of very short oligomers. We believe that the efficient condensation reaction occurs in a hydrogen-bonded tetrahelical aggregate of a type that is known to form with many guanosine derivatives.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02103623
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  • 7
    Electronic Resource
    Electronic Resource
    Selective amidation of carboxyl groups of the intermolecular contact regions of hemoglobin S: Structural aspects (1989)
    Springer
    The protein journal 8 (1989), S. 231-237 
    Details
    ISSN: 1573-4943
    Keywords: Polymerization ; carboxylate reactivity ; isopeptide bond ; erythrocyte sickling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Carboxyl groups of HbS are readily activated by water-soluble carbodiimide atpH 6.0 and room temperature. These o-acylurea intermediates (activated carboxyl) are accessible for nucleophilic attack by amines. With glycine ethyl ester, the amidation is very selective for the γ-carboxyl of Glu-43(β) and more than 65% of the glycine ethyl ester incorporated is on this carboxyl group. In contrast, glucosamine derivatizes the γ-carboxyl group of Glu-22(β) as well as that of Glu-43(β) to nearly the same degree. However, the total amidation of HbS by glucosamine is lower than that with glycine ethyl ester. The differential selectivity of the two amines is apparently related to the differences in the microenvironment of the γ-carboxyl groups of Glu-22(β) and Glu-43(β), which either facilitates or refracts the aminolysis of the activated carboxyl with the two amines to different degrees. The carboxyl groups of isolated β-chain exhibit a higher reactivity for amidation with glycine ethyl ester than does the tetramer. The carboxyl groups of Glu-22(β) and Glu-43(β) and that of Asp-47(β) are all activated by carbodiimide suggesting that the higherpKa of these carboxyl groups (facilitating the activation) is a property of tertiary interaction of the polypeptide chain. The interaction of the β-chain with α-chain, i.e., generation of the quaternary interactions, reduces overall reactivity of the carboxyl groups of the protein. The higher selectivity of hemoglobin S for amidation at Glu-43(β) with glycine ethyl ester compared with that of isolated β-chain appears to be primarily a consequence of decreased amidation at sites other than at Glu-43(β).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01024946
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  • 8
    Electronic Resource
    Electronic Resource
    Unifying principles in intermediate filament (IF) structure and assembly (1988)
    Springer
    Protoplasma 145 (1988), S. 73-81 
    Details
    ISSN: 1615-6102
    Keywords: Intermediate filament structure ; Intermediate filament assembly ; Desmin ; Keratins ; Neurofilaments ; Nuclear lamins ; Cytoskeleton ; Electron microscopy ; Polymerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01349341
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  • 9
    Electronic Resource
    Electronic Resource
    Comportement rhéologique de sols d'acide polysilicique. (1988)
    Springer
    Rheologica acta 27 (1988), S. 52-60 
    Details
    ISSN: 1435-1528
    Keywords: Polymerization ; sol-geltransition ; breakpoint ; pH value ; polysilicic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Abstract The rheological behaviour of silicic acid in aqueous solutions was studied over a period of time for pH values between 6 and 8 at the concentration 10 g ⋅ 1−1, and at pH = 8 for different concentrations varying from 0.5 to 10 g ⋅ 1−1. The shear stress-shear rate curves indicate a very complex character of rheological behaviour. Its analysis with respect to the influence of time, pH and concentration contributes to the knowledge of the structure of the polymer during the process of gel formation. It is shown that the inital shear-thickening behaviour of the colloïdal sol at low concentrations is followed by a shear-thinning behaviour under conditions of polymerization of the silicic acid. The sol-gel transition is marked by a breakpoint. When measurements pass beyond this point, plastic flow behaviour is observed because of the shear induced formation of amorphous silicic aggregates. All rheological processes of silicic acid sols are intensified at pH = 8.
    Notes: Résumé Le comportement rhéologique de sols d'acide silicique a été examiné au cours du temps à des pH compris entre 6 et 8 à la concentration de 10 g ⋅ 1−1 de silice, et à pH = 8 à des concentrations variant entre 0,5 et 10 g ⋅ 1−1. Les courbes d'écoulement révélent un comportement rhéologique complexe. L'analyse des rhéogrammes en fonction du temps, du pH et de la concentration contribue à la connaissance de l'état structural du polymère au cours de la formation du gel. Il ressort que le comportement initialement rhéoépaississant aux faibles concentrations correspondant à l'état d'une solution colloïdale, laisse place à un écoulement rhéofluidifiant dans les conditions favorables á la polymérisation de l'acide silicique. La transition sol-gel est marquée par un breakpoint; en prolongeant les mesures on observe un comportement plastique dû à l'apparition d'agrégats sous l'effet du cisaillement. Tous les processus rhéologiques se trouvent exacerbées à pH = 8.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01372450
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  • 10
    Electronic Resource
    Electronic Resource
    Contributions to Organo-Nickel ChemistryIncluding unpublished results by A. Aradi, O. Behrens, H. Kuhn, T. Leven, J. Neuffer, J. Monkiewicz, K. R. Pörschke, L. Stehling, and K. H. Walter and unpublished crystal structure determinations by C. Krüger, E. Raabe, and Y.-H. Tsay, and model calculations by K. Angermund. The preceding page shows Figure 19 of this article. (1988)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 27 (1988), S. 185-206 
    Details
    ISSN: 0570-0833
    Keywords: Organonickel compounds ; Polymerization ; Hydrogenation ; Homogeneous catalysis ; Catalysis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: One hundred years of organonickel chemistry have generated a wealth of new knowledge and a history of examples of accidental discoveries which have finally led to industrial applications. The historical development is associated with the names of Mond, Sabatier, Reppe and Ziegler and, with the methods and techniques available today, many of the original discoveries and unsolved problems are attracting renewed attention. For example, 70 years were to go by before a synthesis first conceived by Sabatier could finally be realized. The path leading from nickel-catalyzed hydrogenation to highly enantioselective homogeneous catalysts is one of the contributions to organonickel chemistry which is described here.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198801851
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  • 11
    Electronic Resource
    Electronic Resource
    An improved method for the polymerization of ethynylferrocene. Conducting properties of doped polyethynylferrocene (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 2 (1988), S. 533-537 
    Details
    ISSN: 0268-2605
    Keywords: Polymerization ; ethynylferrocene ; conductivity ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The catalytic activity of the [Rh(cod)Cl]2 complex (cod = cis, cis-cyclo-octa-1,5-diene) with respect to the polymerization of ethynylferrocene (EFc) was examined. A good yield (about 80%) of polyethynylferrocene (PEFc) was obtained in benzene by addition of sodium hydroxide as co-catalyst. PEFc was insoluble in most organic solvents. The conductivity (s̰) of the undoped polymer is about 10-11 ohm-1 cm-1; upon doping PEFc with iodine in tetrahydrofuran the conductivity can be increased to 10-100 ohm-1 cm-1. The influence of other doping agents was also examined.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aoc.590020606
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  • 12
    Electronic Resource
    Electronic Resource
    Oligoglyceric acid synthesis by autocondensation of glyceroyl thioester (1987)
    Springer
    Journal of molecular evolution 25 (1987), S. 191-196 
    Details
    ISSN: 1432-1432
    Keywords: Glyceroyl thioester ; Polymerization ; Polyester ; Oligoglyceric acid ; Thioester ; Prebiotic chemistry ; Molecular evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The autocondensation of the glyceroyl thioesterS-glyceroyl-ethanethiol yielded oligoglyceric acid. The rates of autocondensation and hydrolysis of the thioester increased from pH 6.5 to pH 7.5 in 2,6-lutidine and imidazole buffers. Autocondensation and hydrolysis were much more rapid in imidazole buffers than in 2,6-lutidine buffers of the same pH. The efficiency of ester bond synthesis was about 20% for 40 mMS-glyceroylethanethiol in 2,6-lutidine and imidazole buffers near neutral pH. The size and yield of the oligoglyceric acid products increased when the concentration of the thioester was increased. The relationship of these results to prebiotic polymer synthesis is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02100011
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  • 13
    Electronic Resource
    Electronic Resource
    1,3-Adamantanyl dimethylsiloxane copolymers. Preparation and properties (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 1 (1987), S. 171-176 
    Details
    ISSN: 0268-2605
    Keywords: Condensation ; Polymerization ; Silyladamantane ; Thermal stability ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,3-bis(Dimethylhydroxysilyl)adamantane(I) has been prepared. Thermal condensation polymerization of this monomer yields poly-1,3-adamantyl-1,1,3,3-tetramethyldisiloxane. Condensation of I with bis(dimethylamino)dimethylsilane or 1,3-bis(dimethylamino)-1,1,3,3-tetramethyldisiloxane gave the expected 1,3-adamantyl dimethylsiloxane copolymers (II and III) respectively. These polymers have been characterized by 1H,13C, and 29SiNMR as well as GPC and TGA. They have unusually high thermal stability.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aoc.590010208
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  • 14
    Electronic Resource
    Electronic Resource
    Stereospecific Homopolymerization of CyclopenteneLecture given by Dall' Asta at the Gordon Research Conference on Polymers, Santa Barbara, Calif. (U.S.A.) in January, 1964, and to the Macromolecular Colloquium in Freiburg/Breisgau (Germany), in March, 1964. (1964)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 3 (1964), S. 723-729 
    Details
    ISSN: 0570-0833
    Keywords: Stereospecific polymerization ; Polymerization ; Polycyclopentene ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of cyclo-olefins, like that of olefins with an internal double bond, is sterically hindered. Within recent years it has become possible to prepare copolymers of these compounds with ethylene, with the aid of anionic coordination Ziegler catalysts. This copolymerization always results in cis-opening of the double bond. Despite the steric hindrance, cyclobutene and cyclopropene have also been homopolymerized, with opening of the double bond. - Rather surprisingly, the best catalysts for homopolymerization of cyclopentene are those which exhibit low activity in the polymerization of ethylene. Ring cleavage occurs with MoCl5/Al(C2H5)3 to give the cis-polypentenamer, whereas WCl6/Al(C2H5)3 gives the trans-polypentenamer. Both polypentenamers exhibit elastomeric properties. - Evidence from infrared spectra and oxidative degradation indicates that the monomer units in the trans-polypentenamer are linked head-to-tail. It is presumably the single bond adjacent to the double bond that is broken. Using X-ray methods at -50 °C, it was possible to determine the crystal structure of the crystalline trans-polypentenamer at about 400% elongation.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196407231
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  • 15
    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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  • 16
    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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  • 17
    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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  • 18
    Electronic Resource
    Electronic Resource
    Pyrrolidone, Capryllactam and Laurolactam as new Monomers for Polyamide FibersFrom a lecture delivered at the meeting of the Plastics and Rubber Section of the Gesellschaft Deutscher Chemiker on April 9th, 1962, in Bad Nauheim (Germany). (1962)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 430-435 
    Details
    ISSN: 0570-0833
    Keywords: Pyrrolidone ; Polyamides ; Fibers ; Lactams ; Polymerization ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The industrial production of capryllactam (1-azacyclononan-2-one) and of laurolactam (1-azacyclotridecan-2-one) starts with cyclization of acetylene or butadeine to give cyclooctatetraene or cyclooctadiene, or cyclization of butadiene to give cyclododecatriene. Further steps are: oxidation of the cyclic hydrocarbon to the ketone, formation of the oxime, and rearrangement of the latter with sulfuric acid. Pyrrolidone can be prepared from acetylene and formaldehyde by way of butyrolactone. The behavior of the lactams during polycondensation is described and the properties of the resulting fibers are compared with those of the known polyamide fibers.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196204301
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    Electronic Resource
    Electronic Resource
    β-Lactams, Their Polymerization and Use as Raw Materials for FibersFrom a lecture delivered on April 9th, 1962 at a meeting of the GDCh-Fachgruppe “Kunstsoffe and Kautschuk” Plastics and Rubber Division of the German Chemical Society in Bad Nauheim. (1962)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 481-488 
    Details
    ISSN: 0570-0833
    Keywords: Lactams ; Polymerization ; Fibers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: β-Lactams can be prepared by cyclization of β-aimno acid esters. Recently they have become available also from olefins by addition of N-carbonysulfamyl chloride (isocyanatosulfonyl chloride) and from aldehydes by reaction with N-carbonylsulfamyl chloride and ketene. Condensative or anionic polymerization results in polyamides the chains of which contain many more amide groups than the chains of polyamides of the nylon-6 type. Hence the new polymers resemble silk moreclosely. Fibers and films can be prepared from solution.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196204811
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    Paper (German National Licenses)
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