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  • Physics  (14)
  • Analytical Chemistry and Spectroscopy  (3)
  • Organic Chemistry  (2)
  • 1980-1984  (19)
  • 1
    Electronic Resource
    Electronic Resource
    Photochemische Reaktionen 115. Mitteilung [1]. Zur Photochemie konjugierter γ,δ-Epoxyenone: Der Einfluss eines Hydroxylsubstituenten in ∊-StellungMit den besten Wünschen Herrn Dr. Willy G. Stoll zum 70. Geburtstag zugeeignet (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2230-2257 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photochemistry of Conjugated γ,δ-Epoxyenones: The Influence of a Hydroxy Substituent in ∊-PositionOn 1n, π*- or 1π,π*-excitation (λ ≥ 347 or λ=254 nm), the ε-hydroxy-γ;,δ-epoxyenone 8 undergoes fission of the C(γ)—O bond followed by the cleavage of the C(δ)-C(ε) bond. This hitherto unknown sequence of reactions is evidenced by the structure determination of the new type products 10-17 and 25, including a synthetic proof for 12 and the X-ray analysis of 11 (X-ray data: triclinic P1; a=7,386(2), b=8,904(4), c=9,684(5)Å; α=82,29(4)°, β=74,46(3)°, γ=82,29(3)°; Z=2).The selective 1π,π*-excitation also induces competitive C(γ)-C(δ) bond cleavage to yield the bicyclic acetal 18 and a ketonium-ylide intermediate a, which photochemically forms a carbene b giving the allene 19 and the cyclopropene 20.On 1n,π*-excitation of the acetate 9 the initial C(γ)-O bond fission is, in contrast to the behaviour of the corresponding alcohol 8, followed by a 1,2-methyl shift affording (E/Z)-28 or by a cyclization-autoxidation process yielding the lactone 29.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19800630813
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  • 2
    Electronic Resource
    Electronic Resource
    Photochemische Reaktionen 130. Mitteilung129. Mitteilung s. [1].. Zur Photochemie von 5,6-Epoxy-1,3-dienen: Der Einfluss eines 7-Hydroxysubstituenten auf die CarbenbildungTeil II; Teil I s. [2]. (1983)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 66 (1983), S. 2236-2251 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photochemistry of 5,6-Epoxy-1,3-dienes: Influence of a 7-Hydroxy Substituent on the Carbene FormationOn singlet excitation (λ=254 nm) in MeCN the hydroxy-epoxydiene (E)-4 undergoes photocleavage to the carbene intermediates d and e as main processes. The carbene d, showing behaviour typical of vinyl carbenes, undergoes addition to the adjacent double bond furnishing the cyclopropenes 5A + B. The carbene e, however, undergoes an insertion reaction into the neighbouring carbinol C,H-bond leading to the enol intermediate 21, which gives rise to the compounds 6A + B and 7A + B. To a lesser extent the products 8A + B are formed via another enol intermediate (32). On photolysis of (E)-4 in MeOH instead of MeCN the enol intermediates 21 and 32 undergo rapid tautomerisation to the ketones 9A + B (main products) and 11.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19830660735
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  • 3
    Electronic Resource
    Electronic Resource
    Physical properties and structure of silk. VII. Crystallization of amorphous silk fibroin induced by immersion in methanol (1981)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 19 (1981), S. 185-186 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1981.180190117
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  • 4
    Electronic Resource
    Electronic Resource
    Strain criterion in nonlinear creep and recovery in concentrated polymer solutions (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 22 (1984), S. 1119-1148 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Transient and steady-state rheological data are reported for several anionic polystyrene solutions in tritolylphosphate (1. 6 〈 cM/ρMc 〈 7). Here c is the concentration of the solution, M is the molecular weight, ρ the density of the undiluted polymer, and Mc the molecular weight between entanglements as determined from zero-shear viscosity. The polystyrene used had Mw = 410,000 and Mw/Mn 〈 1.06. Data are also given for solutions of polyisobutylene and poly(vinyl acetate) with larger Mw/Mn. The results give a critical strain γ′ ∝ c-1 such that linear viscoelastic behavior was obtained in a simple shear deformation with shear less than γ′. A simplified version of the constitutive equation of Bernstein, Kearsley, and Zapas is used with an empirical strain function F (γ) which contains γ′ as a parameter to discuss transient and steady-state behavior in terms of the distribution of relaxation (or retardation) times determined for linear viscoelastic responce. Features of the dependence of the steady-state viscosity ηk, recoverable compliance Rk, the first-normal stress function Nk(1) on shear rate k are discussed in terms of F (γ) and the distribution of relaxation times to conclude that the latter plays a dominant role in the behavior observed in the range of k usually studied. The results predict that the reduced functions ηk/η0, Rk/R0, and Nk(1)/N0(1) should depend on η0R0k, and that the functional form depends markedly on the distribution of relaxation times, at least in the range η0R0k 〈 102. Comparison with the mechanistic model of Doi and Edwards shows a similar F (γ) but substantial differences in the reduced functions caused by a very narrow distribution of relaxation times in the model.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.180220614
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  • 5
    Electronic Resource
    Electronic Resource
    Low-temperature dielectric relaxation in poly(4,4′-oxydiphenylene pyromellitimide) (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 22 (1984), S. 1399-1405 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of end groups on the low-temperature dielectric relaxation in poly(4,4′-oxydiphenylene pyromellitimide) has been studied using three kinds of samples with different content of anhydride end groups. The magnitude of the dielectric loss peak, designated here the V peak, which appears near -40°C at 1 kHz, depends on the content of anhydride end groups. If a sample with few anhydride end groups is allowed to absorb water, a loss peak appears near the temperature region of the V peak, but it disappears after subsequent heating. In contrast, a sample having a larger amount of anhydride end groups exhibits a large V peak which remains even after further heating. We conclude that the —O—portion of the anhydride end groups is responsible for the V peak, though there may be an additional contribution from absorbed water.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.180220804
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  • 6
    Electronic Resource
    Electronic Resource
    Influence of metabolic fuel on the 13C/12C ratio of breath CO2 (1984)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 11 (1984), S. 557-561 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Natural differences in 13C/12C ratios of various metabolic fuels can produce systematic changes in the 13C/12C ratio of breath CO2, and therefore introduce errors into 13CO2 breath tests. To gain insight into the potential problem, we compared 13C/12C ratios of plasma macronutrients to those of breath CO2 under conditions that should alter the percentages of carbohydrate and lipid being oxidized. In rats, 48 h of starvation decreased the 13C/12C ratio of breath CO2 by 3.5‰. At this time the 13C/12C ratio of breath CO2 was very similar to that of plasma lipids. In humans, 30 min of heavy exercise increased the breath 13CO2/12CO2 ratio by 1.3‰. These changes in breath 13C/12C ratios could be predicted from 13C/12C ratios of plasma macronutrients and the percentage of carbon dioxide derived from each macronutrient, but only when compared within the same populations. For example, the 13C/12C ratios of plasma macronutrients of residents of Chicago, Illinois (USA) and Tokyo (Japan) differed by 1-3‰. An empirical correction of 13CO2 breath test data is recommended when breath tests are run under conditions that will change metabolic fuel utilization.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200111103
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  • 7
    Electronic Resource
    Electronic Resource
    Polycondensation of diethyl mucate with hexamethylenediamine in the presence of poly(vinyl pyridine) (1980)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 933-938 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polycondensation reaction of diethyl mucate (DEM) with hexamethylenediamine (HMD) was carried out in dimethyl sulfoxide (DMSO) at 60°C in the presence of poly(vinyl pyridine) (P-VPy) as a matrix polymer, which was expected to interact with DEM or the resulting polyamide which had pendant hydroxyl groups due to a hydrogen bonding. It was found that the polycondensation of DEM with HMD in the presence of poly(4-vinyl pyridine) (P-4VPy) produced a polyamide with a higher molecular weight than those in the presence of poly(2-vinyl pyridine) (P-2VPy) or in the absence of P-4VPy. The rate of the polycondensation, however, was rarely enhanced by polymer matrixes such as P-4VPy and P-2VPy. During polycondensation in the presence of P-4VPy a gelation of the reaction mixture was observed when the solution was kept at 30°C for several days. This might be ascribed to the formation of the polymer complex between resulting polyamide and P-4VPy during the polycondensation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1980.170180314
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  • 8
    Electronic Resource
    Electronic Resource
    Polycondensation reaction of dimethyl tartrate with hexamethylenediamine in the presence of various matrices (1980)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 939-948 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polycondensation reaction of dimethyl tartrate (DMT) with hexamethylenediamine (HMD) was carried out in dimethyl sulfoxide (DMSO) at 60°C in the presence of various polymer matrices, which were expected to interact with DMT or the resulting polyamide which had pendant hydroxyl groups due to hydrogen bonding. It was found that the rate of polycondensation was enhanced by polymer matrices such as poly(vinyl pyrrolidone) (PVP), Pullulan (polysaccharide) (PF), and poly(vinyl alcohol) (PVA). The rate enhancement became more pronounced with increasing molecular weight of the polymer matrix. When polycondensation in the presence of PVA was carried out in DMSO, a polymer complex was produced. The formation of the polymer complex between the resulting polyamide and PVA during polycondensation was dependent on the concentration of monomers and also on PVA; a gelation of the solution was observed at a concentration of PVA.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1980.170180315
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  • 9
    Electronic Resource
    Electronic Resource
    Thermal degradation of poly[(tetramethyl-p-silphenylene) siloxane] (1981)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 19 (1981), S. 2595-2607 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For the purpose of studying the mechanism of thermal degradation of poly[(tetramethyl-p-silphenylene) Siloxane] (poly TMPS) a series of polymers with silphenylene and siloxane bonds in the main chain were prepared and subjected to thermogravimetry (TG) and pyrolysis study. Analyses of products from poly TMPS degradation (in vacuum at a constant temperature) by gas chromatography (GC), infrared (IR), nuclear magnetic resonance (NMR) spectroscopy, and gas chromatography-mass spectrometry (GC-MS) revealed that degradation occurs at the silphenylene bonds. The TG curves obtained in He for heating rates of 1,2,2.5,7.5, and 10°C/min were analyzed by the Ozawa method; activation energies of 39 ± 1 and 45 ± 2 kcal/mol were obtained respectively for the initial cleavage of the methyl side group and the later-stage scission of the main-chain silphenylene bond which leads to a major weight loss. The results agree with those obtained for other structurally similar polymers.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1981.170191019
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  • 10
    Electronic Resource
    Electronic Resource
    Studies on suspension and emulsion. XXXV. Effect of epoxy groups at the surface layer of ethyl acrylate-glycidyl methacrylate copolymer emulsion particles on its crosslinking reactivity (1980)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2451-2459 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of epoxy groups at the surface layer of ethyl acrylate-glycidyl methacrylate copolymer (1) emulsion particles on its crosslinking reactivity has been investigated. For this purpose two series of I emulsions were prepared. In the Y series, of which emulsion particles have epoxy groups at the surface layer, the epoxy content in the polymerization recipe was varied. For preparing the X series, of which emulsion particles have few epoxy groups at the surface layer, the high epoxy content of a given emulsion was reduced by various degrees of cleavage reaction with HCl-CaCl2. In emulsion blend films with amine-group-containing copolymer (II) emulsion, where the crosslinking reaction was expected to proceed only at the interfacial layer of I and II emulsion particles, the Y series, compared to the X series at the equal overall epoxy content in particles, showed less swelling and higher gel fraction in dioxane, less swelling in water, and higher tensile strength and modulus. On the other hand, this difference was not observed in the next two crosslinked films in which crosslinking was expected to be homogeneous. First, blends of I and II, which were isolated from the corresponding emulsions discussed above, were cast from dioxane solutions. Second, I emulsions were cast with BF3 ether complex which was expected to penetrate into the particles. It is concluded that the response of I emulsion cleaving the epoxy groups at the surface layer of particles to subsequent interfacial crosslinking is obviously reduced. However, even such an emulsion can be crosslinked to an extent similar to that of an uncleaved emulsion with similar overall epoxy content, if the crosslinking reaction is conducted so as to give an homogeneous effect.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1980.170180804
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