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  • 1960-1964  (24)
  • 1925-1929
  • 1920-1924
  • 1905-1909
  • Fibers  (8)
  • Reaction mechanisms  (6)
  • Alkenes  (5)
  • Phosphorus  (5)
Materialart
Erscheinungszeitraum
Jahr
  • 1
    ISSN: 0570-0833
    Schlagwort(e): Willgerodt-Kindler reaction ; Ketones ; Reaction mechanisms ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Ketones react with sulfur and NH3 or amines at room temperature to produce Δ3-thiazolines, 5-alkylidene-Δ3-thiazolines, Δ3-imidazoline-5-thiones, hexathiacycloheptane derivatives, α,α′-dioxodisulfides, bis-(1-aralk-1-yl) disulfides, or thiocarboxamides, depending on the coreactant and on the reaction conditions. It was recognized that the formation of all of these numerous types of compounds can be explained basically by primary thiolations and geminal dithiolations, which in conjunction with their reverse reaction (desulfurization) and the assumption of a thioreductone equilibrium permit a new interpretation of the course of the Willgerodt-Kindler reaction of alkyl aryl ketones.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 3 (1964), S. 245-249 
    ISSN: 0570-0833
    Schlagwort(e): Addition ; Alkenes ; Electrophilic reactions ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Various structures have been proposed for the intermediates of electrophilic additions onto olefins; these include halonium ions, classical carbonium ions, π-complexes (i.e. nonclassical carbonium ions), and π-complexes with back-coordination. It is shown here that it is impossible to use any one of these entities alone to explain all such electrophilic additions; the electrophile itself determines the nature of the transition state formed. Polar addition of hydrogen halides onto olefins appears to proceed via a classical carbonium ion which does not occur as the free ion but as an undissociated ion pair. Various other mechanisms have been excluded by studies reported here of the stereochemical course of such additions.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 3 (1964), S. 453-460 
    ISSN: 0570-0833
    Schlagwort(e): Tetradentate ligands ; P ligands ; Arsenic ligands ; Phosphorus ; Arsenic ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The effect of ligand shape on coordination numbers and geometry of coordination compounds has been studied using two tetradentate ligands containing phosphorus and arsenic. These tend to form five-coordinate complexes with trigonal bipyramidal structure [Fe(II), Co(I), Co(II), Rh(I), Ni(II), Pd(II), Pt(II)], but can also form six-coordinate complexes with octahedral structure [Fe(II), Ru(II), Os(II), Co(III), Rh(III), Pd(IV), Pt(IV)]. The magnetic properties and the stereochemistry of the complexes are explained by ligand field theory which predicts that, for metal ions with d6-electronic configuration, a low overall field strength should favor the formation of five-coordinate paramagnetic complexes while a high overall field strength should favor the formation of six-coordinate diamagnetic complexes. - This work provides further indication that the tendency of polydentate ligands to use all the potential donor atoms is not as pronounced as is generally believed. This is shown by the isolation of chromium(III) complexes in which the tetradentate ligands are, in fact, acting as tridentate, and by the isolation of mercury(II) complexes where only two of the four donor atoms of the polydentate ligand are actually bonded to the central metal atom.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 3 (1964), S. 93-101 
    ISSN: 0570-0833
    Schlagwort(e): Organometallic catalysts ; Catalysis ; Reaction mechanisms ; Lithium ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Kinetic investigations of the polyreaction of isoprene with organolithium compounds as initiators in n-heptane as solvent indicate the following sequence of reactions: 1. formation of an adduct between a monomeric form of the organolithium compound and the isoprene and 2. reaction of this adduct with an associated form of the organolithium compound with insertion of the isoprene. The adduct formation is considered to be due to chemisorption, and proof of such chemisorption of a monomer (ethylene) is also demonstrated for a homogeneous Ziegler-type catalyst. All the reactions can be formulated in the form of cyclic structures with electron-deficient character. Postulation of such ring structures explains the surprising values obtained for the frequency factors and equilibrium constants.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 3 (1964), S. 460-470 
    ISSN: 0570-0833
    Schlagwort(e): Heat resistance ; Fibers ; Polymers ; Materials science ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: This survey is principally concerned with papers published since 1959 on hydrocarbon polymers, aliphatic poly(terephthalamide) fibers, poly(hydroxybenzoic acid) films, poly(oxadiazole) fibers, poly(benzimidazole) films, poly(phenyltriazole) films, poly(pyromellitimide) films, and fibers from cyclized poly(acrylonitrile). All these materials have extremely high melting points and satisfactory in-use characteristics at high temperatures.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 6
    ISSN: 0570-0833
    Schlagwort(e): Kinetics ; Dipolar cycloaddition ; Cycloaddition ; Heterocycles ; Reaction mechanisms ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Criteria for the mechanism of 1,3-dipolar cycloadditions which lead to 5-membered rings are provided by the stereoselectivity observed with cis-trans isomeric dipolarophiles, by the effect of solvent and substituents on the rate constants, by the activation parameters, and by orientation phenomena. A concerted addition, which can also be described in terms of molecular orbitals and in which the two new σ-bonds are formed simultaneously, although not necessarily at equal rates, offers the best explanation of the experimental facts.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 7
    ISSN: 0570-0833
    Schlagwort(e): Koch carboxylic acid synthesis ; Carboxylic acids ; Alkenes ; Isomerization ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: When straight-chain mono-olefins, from pentene to decene, are subjected to the Koch carboxylic acid synthesis by the addition of CO and H2O or CH3OH in the presence of strongly acidic catalysts, not only the expected secondary acids, but also mixtures of a specific type of tertiary acids or their methyl esters are formed. When the catalysts contain boron trifluoride, the secondary acids are formed in ratios of isomers which are, within the scope of this investigation, independent of the experimental conditions and which agree well with the values calculated from the isomer equilibria of the corresponding n-olefins. Using concentrated sulfuric acid as catalyst, a larger proportion of tertiary acids is obtained than with BF3-catalysis, and amongst the secondary acids, those isomers predominate in which the COOH group is situated near the centre of the molecule.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 723-735 
    ISSN: 0570-0833
    Schlagwort(e): Phenol oxidation ; C-C coupling ; Reaction mechanisms ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The use of well-known phenol oxidation reactions for the preparation of compounds arising from C—C and C—O coupling has recently received increased attention. A selection from the large number of products obtainable by oxidation of mono- and polyhydric phenols and a discussion of the reaction mechanisms indicate the scope of this method. The formation of hydroxyphenylquinones and orceine dyes from resorcinol derivatives is explained. The synthesis of natural products by way of phenol oxidations is briefly discussed.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 295-308 
    ISSN: 0570-0833
    Schlagwort(e): Emulsion polymerization ; Polymerization ; Polymerization ; Alkenes ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 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.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 523-530 
    ISSN: 0570-0833
    Schlagwort(e): Semimetals ; Metallic structure ; Nonmetallic structure ; Antimony ; Arsenic ; Bismuth ; Phosphorus ; Tellurium ; Tin ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Measurements on semimetals have been continued. Studies of the dependence on temperature of various properties have provided details regarding the transition from the nonmetallic to the more metallic structure. A second-order transition has been found for tin at 170 °C, in which the c-axis remains unchanged, while the a-axis undergoes a small, discontinuous elongation.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 646-654 
    ISSN: 0570-0833
    Schlagwort(e): Polyphosphanes ; Phosphanes ; Phosphorus ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: While silicon and sulfur, which are situated to the left and to the right of phosphorus in the periodic table, from numerous chain and cyclic Si-Si and S-S-compounds with varying numbers of members, until recently the polyphosphance chemistry has been limited to the two-membered compounds diphosphane P2H4 and its derivatives. A number of results obtained in studies on polyphosphanes carried out in recent years will therefore be discussed, which, together with some more recent work by other authors, have led to an expansion of our knowledge of the prepration and properties of straight and branched-chain as well as of cyclic and polycylic -P-P-systems.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 704-714 
    ISSN: 0570-0833
    Schlagwort(e): Titanium ; Alkenes ; Polymerization ; Titanium ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 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.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 410-420 
    ISSN: 0570-0833
    Schlagwort(e): Oligomers ; Pleionomers ; Polymers ; Fibers ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The term “oligomer” is defined, and a survey of methods for the isolation and synthesis of cyclic and linear oligoesters, oligourethanes, oligo(acrylonitriles), and oligoamides is presented. The oligomers serve a valuable function as model substances for the investigation of many properties of the corresponding high polymers. This is shown using several examples (infrared spectroscopy, X-ray spectroscopy, viscosity).
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 80-88 
    ISSN: 0570-0833
    Schlagwort(e): Oxidation ; Palladium ; Catalysis ; Alkenes ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The oxidation of olefins to carbonyl compounds with palladium compounds, especially the oxidation of ethylene to acetaldehyde, is at present carried out on a technical scale. The reaction takes place via a palladium-olefin complex, the formation of which is inhibited by halide ions. Hydrolysis to the carbonyl compound is inhibited by hydrogen ions. The knowledge gained by studying the reaction of olefins with pure solutions of palladium salts allows important conclusions to be drawn concerning the action of technical catalyst solutions containing copper and palladium chloride.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 15
    ISSN: 0570-0833
    Schlagwort(e): Elimination ; Reaction mechanisms ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In bimolecular β-elimination (E 2 mechanism), several bonds are ruptured or formed in one concerted reaction step. However, the various aspects of bond-making or -breaking need not be completely synchronous. In the E 2 transition state for elimination HX, rupture of the C—X bond may be more advanced than that of the C—H linkage, or vice versa. Factors influencing the relative extents of rupture of these two bonds at the transition state are discussed, and the consequences of non-synchroneity in one sense or the other are developed from theory and illustrated from experiment. This treatment provides an understanding of the Hofmann-vs.-Saytzeff orientation problem.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 16
    ISSN: 0570-0833
    Schlagwort(e): Pyrrolidone ; Polyamides ; Fibers ; Lactams ; Polymerization ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 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.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 617-621 
    ISSN: 0570-0833
    Schlagwort(e): Isocyanates ; Phosphorus ; Silicon ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Several aminoaryl esters of phosphoric and thiophosphoric acids were prepared by the reaction of phosphorus pentahalides with nitrophenols, followed by catalytic hydrogenation, or by treating aminophenols with phosphorus trihalides and oxidation to pentavalent phosphorus. These amino esters were then converted into isocyanato esters by the action of phosgene. Isocyanates of phosphonates have been synthetized on the same principle, as well as via the Arbusov reaction of halogen-substituted isocyanates with trialkyl phosphites. The reaction of silicon halides or alkylhalogenosilanes with aminophenols yielded aminoaryl esters of silicic acid or its derivatives, which could also be treated with phosgene to convert them into isocyanato esters.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 652-656 
    ISSN: 0570-0833
    Schlagwort(e): β-Chloroethanephosphonic dichloride ; Phosphorus ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Ethylene, phosphorus trichloride, and oxygen react together to give β-chloroethylphosphonic dichloride in good yields. Being a bifunctional acid chloride, this compound undergoes polycondensation reactions with other, at least bifunctional, compounds affording polyesters, polyamides, epoxy resins, etc. β-Chloroethylphosphonic dichloride also may be converted into vinylphosphonic dichloride, thus serving as a starting material for the preparation of vinylphosphonic acid and its derivatives. These undergo both homopolymerization and copolymerization with compounds containing olefinic double bonds. The products are used in the field of synthetic resins, for dressing textiles, and as protective surface coatings.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 382-393 
    ISSN: 0570-0833
    Schlagwort(e): Electrophilic reactions ; Reaction mechanisms ; Substitution ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The results obtained in recent years from investigations into the mechanisms of electrophilic substitution reaction at sp3-hybridized carbon atoms are reviewed.
    Materialart: Digitale Medien
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  • 20
    ISSN: 0570-0833
    Schlagwort(e): Lactams ; Polymerization ; Fibers ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 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.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 532-537 
    ISSN: 0570-0833
    Schlagwort(e): Polyacrylonitrile ; Fibers ; Azatrimethinecyanines ; Dyes/Pigments ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Like all basic dyes, azatrimethinecyanines possess a good dyeing affinity for acrylic fibers. Compounds with isolated nitrogen atoms in the trimethine chain show insufficient light fastness, whereas good to excellent fastness to light is displayed by compounds having neighboring nitrogen atoms in the chain. Thus, a working hypothesis stating that the light fastness of trimethinecyanines on acrylic fibers is improved by progressive replacement of methine groups by nitrogen atoms has been partially confirmed.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
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  • 22
    ISSN: 0570-0833
    Schlagwort(e): Elastomers ; Fibers ; Polyurethanes ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Highly elastic polyurethanes suitable for fiber production can be obtained by various synthetic routes based on diisocyanate polyaddition processes. Macrodiisocyanates obtained from long chain diols and diisocyanates are allowed to react with polyamines during fiber formation (chemical spinning process) or the macrodiisocyanates are treated in solvents (e.g. dimethylformamide) with polyamines to give highly viscous, spinnable solutions of polymer. Both methods yield highly elastic polymers with wide-mesh network structures. The production of polyurethane fibers and their structures and physical properties are described.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 23
    ISSN: 0570-0833
    Schlagwort(e): Copolymers ; Fibers ; Vinylidenedicarbonitrile ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Vinyldendicarbonitrile (Vinylidene cyanide) on free redical catalyzed copolymerization shows a much stronger tendency to form 1:1 alternating copolymers than acrylonitrile. While bulk poly(vinylidene cyanide) fails to crystallize, despite its molecular symmetry, several alternating copolymers are readily crystallizable, notably those containing butadiene, isoprene, isobutylene, or vinylidene chloride. Fibers have been prepared from a number of the higher melting copolymers and examined for physical properties. Fibers from the vinyl acetate and vinyl chloride copolymers show expectional elastic behavior both when dry and wet. The fiber from the vinylidene cyanide |vinyl acetate alternating copolymer (Darvan® nytril fiber) is only moderately oriented and is characterized by exceptional softness and excellent elastic recovery and resilience, both when dry and wet.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 24
    ISSN: 0570-0833
    Schlagwort(e): Long periods ; Polyethylene ; Fibers ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Meridional reflections appearing in small-angle X-ray diffraction diagrams of drawn polyethylene are caused by a nearly periodic arrangement of crystalline and disordered regions. The long period, which is determined by the average distance between two consecutive crystallites, depends on the method of preparing the sample. The time and temperature dependences of the positions of the small-angle reflections have been investigated. The growth of the long period of unoriented bulk polyethlene and polyethylene single crystal follows the same time dependence as that of stretched films. However, characteristic differences were obseved in the relationship between density and long period; they are attributed to the fact that in single crystals and in material crystallized from the melt, the chains are folded at the boundaries of the crystallites, whereas this in not the case in stretched polyethylene.
    Zusätzliches Material: 25 Ill.
    Materialart: Digitale Medien
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