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  • 1985-1989
  • 1970-1974  (887)
  • 1972  (887)
  • Physics  (555)
  • Analytical Chemistry and Spectroscopy  (332)
  • 1
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 51-69 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Photoelastic investigations have been carried out on a number of polymers in the crosslinked rubbery state. These include cis-polyisoprene, two polybutadienes of different structural configurations, an ethylene-propylene terpolymer, and a range of styrene - butadiene copolymers. From the measured values of stress-optical coefficients, together with calculated values of the optical anisotropies of the monomer units in the chain (based on Denbigh's values of bond polarizabilities), estimates are made of the number of monomer units in the equivalent random link (of the Kuhn-Grün theory) for the polymeric chains considered. Further, from a study of the temperature dependence of the stress-optical coefficient, the temperature dependence of the lenght of the equivalent random link, and hence of the statistical length of the chain, is derived. The interpretation of the temperature dependence data is discussed in a semiquantitative manner in terms of internal energy differences between different rotational states.
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  • 2
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Domain structures of solvent-cast films of A-B-A block copolymers of styrene-isoprene-styrene were studied by electron microscopy by use of the OsO4 fixation technique. The effects of varying proportions of the two components and the casting solvent upon the domain structures were examined. It is concluded that the domain formation mechanism can be discussed like that of A-B block copolymers irrespective of sequence arrangements, as Matsuo et al. suggested, by treating A-B-A or B-A-B block copolymers as A-(1/2)B or B-(1/2)A block copolymers. The five types of fundamental domain structures - spherical domains of component A in a matrix of component B, rodlike domains of A in a matrix of B, alternating lamellae of the two components, rodlike domains of B in a matrix of A, and spherical domains of B in a matrix of A - are achieved mainly by the change of the fractional composition of the two components for a given solvent. One of the most significant features of the A-B-A block copolymers in contrast to the A-B block copolymers, i.e., that A-B-A chains can interconnect two A domains, was explored by investigating (1) the swelling behavior in a solvent that is a good one for isoprene but a nonsolvent for styrene and (2) mechanical behavior above the glass transition temperature of the styrene segments.
    Additional Material: 13 Ill.
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  • 3
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: On the basis of our own experimental and some literature data, the contributions of slow relaxation mechanisms to the shear modulus, (GeN  -  Ge), and the parameter C2 of the Mooney-Rivlin equation have been examined for lightly crosslinked poly(butyl methacrylate), poly(butyl acrylate), poly(2-hydroxyethyl methacrylate), and some rubber networks. For the rubbers, increasing degree of crosslinking caused a decrease in GeN  -  Ge and an increase in C2; for the other networks, both GeN  -  Ge and C2 diminished with increasing crosslinking. The effectiveness of the crosslinking polymerization, and also the absolute values of the physical crosslinking degree, decreased in the order of poly(2-hydroxyethyl methacrylate), poly(butyl methacrylate), and poly(butyl acrylate). The values of the equilibrium compliances J of the networks studied, obtained by various methods, have also been compared, and good agreement has been found.
    Additional Material: 9 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 375-376 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 519-526 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Starting from the Lorentz-Lorenz equation, Heller, a few years ago, advanced a method for calculating the partial specific volume of a substance in a dilute solution from the refractive index increment of the solution and the specific refraction of the solute. It is shown that this method, based on graphical extrapolation, can be considerably simplified. Further, a method is indicated by which the partial specific volume of a substance over the whole range of concentrations can be calculated in an analogous manner. The method is checked and elucidated with reference to some experimental examples.
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 549-563 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The structures of copolymers of ethylene and chlorotrifluoroethylene have been studied by infrared, nuclear magnetic resonance, and x-ray diffraction techniques. Copolymers varying in ethylene composition from 80 to 50 mole-% were prepared at a number of different temperatures with a peroxide catalyst system. Compositions of 50/50 mole ratio were found to be semicrystalline and to have melting points as high as 241°C. These materials were found to be copolymers with a high degree of one-to-one alternation. They were similar in structure to 1:1 copolymers which had been reported previously by other workers who used a triethylboron catalyst system. The x-ray evidence indicated that the copolymers prepared with the peroxide catalysts were not stereoregular. A hexagonal unit cell with a theoretical density of 1.70 g/cc was determined for the alternating one-to-one copolymer by x-ray techniques. A value of 262°C was determined for the melting point of the theoretical 100% alternating one-to-one copolymer. Values of ΔHƒ = 4500 cal/mole and ΔSƒ = 8.4 cal/deg-mole were also calculated for the alternating 1:1 copolymer. The preferred conformation of the material appears to be a “kinked” structure with the crystalline phase having ethylene units in one chain lining up opposite chlorotrifluoroethylene units in the adjacent chain. Polar association which can occur between fluorine and hydrogen atoms in this arrangement may account in part for the relatively high melting point of the alternating one-to-one copolymers.
    Additional Material: 7 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 577-584 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A study of rat-tail tendon fibers, about 200 μ in diameter, by scanning electron microscopy of fractured specimens reveals that these crimped fibers are largely made up of cylindrical units, about 10 μ in diameter. These, in turn, are made up of the well-known collagen fibrils, ca. 0.1 μ in diameter, which have been observed previously by transmission electron microscopy and small-angle x-ray diffraction. Both the 10-μ and 0.1-μ cylindrical units were found to be arranged parallel to the macroscopic fiber axis rather than helically about it, as has been often proposed in the past. Significant improvement in resolution of the fracture surfaces was obtained by dehydration of the tendon. Microscopy of undehydrated tendon fibers undergoing solubilization by dilute aqueous acetic acid confirmed the results obtained by fractography.
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 615-629 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The energy of the ground state, charge distribution, and bond orders were calculated by a MO method in the SCF-CNDO/2 approximation for various configurations of the monomer, dimer, and trimer model of both the associated and dissociated reaction center of an anionic acetylene polymerization. According to the results of these calculations, cooperation of π and σ bonds leads to a charge delocalization which increases with growing chain length and is the reason for kinetic deactivation of the center. Propagation is stopped, probably by a cooperative effect of the kinetic and thermodynamic factors.
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 863-875 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Folded-chain crystals of certain polyamides present some novel diffraction effects due to the small number of repeat units within the lamellar thickness. X-ray diffraction evidence is available in the complete range from low to wide angles. This information is interpreted in terms of the structure factor of an individual lamella together with the lattice factor appropriate for the stacking of lamellae. When due account is taken of the lattice factor, whose effect can be detected even at large angles, three features of the lamellar structure can be deduced. First, the evidence is in favor of the straight-chain stems traversing almost the total thickness of each lamella, implying sharp folds at the lamellar surfaces. Some consequences of this result on the interpretation of data obtained from annealed mats are mentioned. Second, the detailed determination of the stem structure demands that the majority of the folds in nylon 66 lie in the acid group. Third, there are regions of depleted electron density at the lamellar surfaces, though features of the crystal structure are still retained. This indicates the presence of some folds deeper in the crystal than the majority.
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 919-936 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Small-angle equatorial x-ray scattering from fibrous systems is often complicated by the effects of morphological organization and/or heterogeneities as well as by macromolecular structure and organization influencing this same region of scattering space. In previous work it was shown that closed form mathematical expressions could be obtained for the Patterson function, without prior assumptions about the scattering system, when the intensity data were purposely truncated. In this paper the use of these expressions to extract the physical parameters describing the scattering system is demonstrated by application to a model system. The expressions are also expanded to include lattice distortions and long range coherency. A second approach is presented for cases when the coherence is small, and finally the use of higher-resolution data is discussed.
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  • 11
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 937-944 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The heats of fusion of low-density polyethylene and chlorinated polyethylenes of varying chlorine content have been investigated by differential scanning colorimetry (DSC). Linear correlations are found between the chlorine content and the apparent heat of fusion, crystallinity, and the maximum specific heat measured in the temperature range 90-120°C. The effect of heat treatment on crystallinity is shown to be strongly dependent on the chlorine content of the polymers.
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  • 12
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 993-1011 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The adsorption of some polyacids, principally poly(acrylic acid), on nylon powder has been studied. In aqueous solutions at low pH the adsorption behavior of poly(acrylic acid) is controlled by adsorbate coil dimensions rather than by electrostatic effects. Less adsorption takes place from methanol solutions but the process is much more rapid than from water. Above a critical value, increase of adsorbate molecular weight leads to a reduced adsorption, the effect being particularly evidenced by aqueous solutions. Model compounds (propionic and glutaric acids) are rapidly adsorbed from both methanol and water, but give low specific absorptions. Adsorption of poly(acrylic acids) and model compounds, is reduced, but not eliminated, by modification of the nylon adsorbent through acetylation or methoxymethylation. The adsorption of poly(acrylic acid) on nylon is not readily reversible; however, partial neutralization will release preadsorbed poly(acrylic acid) from nylon powder. The adsorption behavior of copolymers of acrylic acid with N-vinylpyrrolidone is reported, as are brief studies on some other homopolyacids. The results are generally interpreted on the basis of sorption of the macromolecules into a swollen, flexible adsorbent.
    Additional Material: 8 Ill.
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  • 13
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1555-1564 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The crystallization kinetics of a range of fractions of poly(ethylene oxide) are presented and analyzed. It is concluded that deviations from the Avrami equation with exponent of 3 are mainly due to rejection of low molecular weight molecules for the low molecular weight fractions (M̄n 〈 6,000) and to a process of crystal perfecting for the high molecular weight fractions (M̄n 〉 6,000).
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  • 14
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1565-1574 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Both crazes and fracture surfaces in glassy polymers produce a low-angle scattering of x-rays. Scattering patterns are anisotropic and often show considerable streaking. In the one case (polystyrene) studied extensively so far, detalied analysis suggests that the craze is approximated as a collection of spheroidal or irregular-shaped voids surrounded by material with anisotropic density distribution arising from its orientation in the stress direction. The void dimension is about 90-115 Å and the specific internal surface area about 170 m2/cm3 of craze. These results and those from electron microscopic studies are reasonably consistent.
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  • 15
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1681-1689 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A simple form of nonisothermal free energy function A(λ1, λ2, λ3, T) for rubberlike materials results from postulating that the entropy is a separable symmetric function of the extension ratios λi along the principal strain directions and considering the fundamental properties of rubberlike materials, i.e., that rubber elasticity is associated primarily with changes in entropy and the variation of elastic tension with changes in temperature is linear. The explicit representation of A is reduced to the Valanis-Landel strain energy function for isothermal cases.
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  • 16
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1719-1729 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Transitions and relaxation phenomena in poly(1,4-phenylene ether) were studied over temperature range from 100 to 800°K by applying a combination of calorimetric, dilatometric, dynamic mechanical, and dielectric techniques. Amorphous polymer, exhibiting no x-ray crystallinity, is obtained only by quenching molten samples at extremely fast cooling rates (ca. 1000°C/sec) and by minimizing thermal gradients within specimens. A weakly active mechanical relaxation region with a loss maximum at 155°K of unknown origin was observed. The glass transition interval of completely amorphous polymer is characterized by a discontinuous jump in heat capacity of 2.76 cal/deg per chain segment occurring at 363°K (corrected for kinetic effects), and a fourfold increase in the coefficient of linear thermal expansion. Strongly active, dynamic mechanical relaxations occur in the Tg interval with a loss maximum at 371°K (f = 110 cps) and resulting in a drop in the dynamic storage modulus from 1011 to 109 dyne/cm2. Cold crystallization takes place just above Tg, to yield a polymer with an x-ray crystallinity of 0.7 and a heat of crystallization of 270 cal/mole. The crystalline polymer shows a complex melt structure. Depending upon the thermal history, multiple endothermic peaks indicative of structural reorganizations occur just prior to fusion. Very high dielectric losses with a wide distribution of relaxation times were observed in the melt interval. The mechanical relaxation spectrum in this region is typical of viscous flow behavior.
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  • 17
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    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1749-1756 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polypropylene fibers prepared by quenching in ice-water were drawn at 25, 80, 120, and 140°C to a draw ratio between 6 and 8 at draw rates 0.05, 0.5, 5, and 50 cm/min. The long period increases almost linearly with the draw rate for drawing at 25°C and decreases for drawing at higher temperatures. The effect in the latter cases is an annealing effect. As a consequence of the shorter exposure of the drawn fibers to the high temperature at higher draw rate, the long-period growth proceeds for a shorter time and hence results in a smaller increase of long period. At 25°C, however, the long-period growth is negligible. The increase of long period with draw rate is the consequence of higher adiabatic heating as calculated from the energy input during the plastic deformation which transforms the spherulitic into the fibrous structure. One concludes that the long period established during this transformation depends on the maximum temperature reached in the micronecking zone and not on the macroscopically observed temperature of the sample in the neck.
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  • 18
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1775-1787 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Mooney's version of the molecular theory of polymer networks has been generalized to the case when the external strain applied in the isotropic state is different from that at network formation. As in the theory of equilibrium behavior of the polymer networks, this generalization allows inclusion in the viscoelastic functions of effects connected with the temperature dependence of internal energy of the chains and with the strain effect of the solvent. From viscoelastic functions thus generalized, it is possible to derive a relation for calculation of the monomeric friction coefficient. It also suggests the possibility of superposing data obtained at various temperatures, degrees of swelling, and condition of network formation.
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  • 19
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    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1837-1839 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
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  • 20
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1799-1809 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of hydrostatic pressure on the crystal structure of PTFE has been studied up to pressures of ca. 25 kbar by x-ray diffraction. The experimental method uses opposed diamond anvils of small surface area as transmitters of pressure with MoKα x-radiation propagating through these anvils. A small specimen of oriented polymer is held in place with a molybdenum gasket. Pressures are measured by change in lattice spacing of sodium chloride included with some specimens. It is found that above 4.5 kbar the PTFE changes to a high-pressure phase in which the molecules have transformed from their normal helical arrangement to that of a planar zigzag and that the planes of the molecules all lie parallel to one another. Further changes in the diffraction pattern on increase in pressure are attributed to slip and twinning in the high-pressure phase rather than to another phase change.
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  • 21
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    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1023-1028 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The adsorption behavior on silica of some polystrenes of moderate molecular weight distribution, both singly and in mixtures, has been examined. The adsorption isotherms indicate that, in both a good solvent (trichloroethylene) and under theta conditions, the species of higher molecular weight is preferentially adsorbed at or near full surface coverage, but that the smaller adsorbate has an improved opportunity for adsorption at low surface coverage. The use of tritiated adsorbates substantiate the isotherm data in cyclohexane solution.
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  • 22
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1047-1059 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Shear stress P21 and normal stress P11 -P22 functions of moderately concentrated aqueous solutions of sodium poly (acrylate) were measured under steady shear flow at various shear rates \documentclass{article}\pagestyle{empty}\begin{document}$\dot \gamma$\end{document} with a Weissenberg rheogoniometer. The compliance function Js = (P11 - P22)/2P212 is found to vary with shear rate. The double logarithmic plot of Js versus \documentclass{article}\pagestyle{empty}\begin{document}$\dot \gamma$\end{document} can be superposed with respect to molecular weight at constant concentrations of added neutral salt and polymer. These reduced plots differ markedly as the concentration of added salt is varied but converge to a single line at high shear rates.
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  • 23
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1085-1095 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In order to study the crazing behavior in rubber-toughened glassy polymers, polystyrene samples containing two rubber balls of the same diameter with varying separations have been prepared. They were subjected to simple tension, and their crazing behavior was observed. When the two balls are close together, the craze-initiation stress is considerably lower than that of single-ball samples. With increase in the distance between the two balls the craze-initiation stress increases at first almost linearly and levels off when l/d reaches about 1.45, where l and d are the center-to-center distance and the diameter of the balls, respectively. When l is sufficiently small, the crazes are seen to develop extensively at the inner surfaces of the balls and finally bridge with each other. The crazes bridged between the balls expand largely in the plane perpendicular to the applied load.
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  • 24
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1061-1084 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dynamic shear modulus and the flow rate through capillaries under constant pressure and under constant velocity of the piston, have been measured for polybutadienes and polyisoprenes of narrow molecular weight distribution with molecular weights ranging, respectively, from 3.8 × 104 to 5.8 × 105 and from 1.06 × 105 to 6.02 × 105. The phenomena of the discontinuous increase of volume flow rate and self-oscillatory flow regime at critical rates of deformation have been considered in detail. It is proposed that these phenomena are due to the induced transition of the polymer from the fluid to the high-elastic state at higher deformation rates. As a result, an inference has been made that polybutadienes and polyisoprenes with a narrow molecular weight distribution in the high-elastic state, behave in certain respects as crosslinked polymers incapable of displaying fluidity. The quantitative relationships among the viscoelastic characteristics measured under dynamic regimes, the parameters determining the critical flow regimes, and the molecular weights of polybutadienes and polyisoprenes have been worked out.
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  • 25
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1029-1045 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dielectric absorption due to terminal polar groups localized in defect regions of polyoxymethylene crystals shows an anisotropy relative to an applied field. An attempt to interpret this anisotropy has been made by applying the barrier theory of Hoffman. The potential energy map for the rotation of the terminal polar group calculated from conformational analysis gives two minima. The angle between the dipole moment of the terminal OH and the fiber axis calculated in terms of the two conformations corresponding to the potential energy minima is in good agreement with results from infrared dichroism. This agreement is considered as evidence that the conformational analysis is reliable for estimating the potential energy minima required in the calculation according to the barrier theory. The barrier height obtained by the conformational analysis and the anisotropy calculated from the components of the dipole moments for the terminal polar group in terms of the barrier theory are in qualitative agreement with the experimental data.
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  • 26
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1111-1117 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The permeation and solubility of propylene in polyethylene films were measured at temperatures and pressures near the condensation point of the vapor. Diffusion coefficients were calculated from these data. On the basis of the behavior of activation energies with relative vapor pressure, it is shown how diffusion and sorption influence permeation phenomena in this region.
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  • 27
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1135-1143 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Melting of various polyethylene structures is compared by using data obtained on the Perkin-Elmer differential scanning calorimeter (DSC). Transparent, high-density samples crystallized under both orientation and pressure in the Instron capillary rheometer are compared with samples crystallized from dilute solution by stirring and with samples crystallized under high pressure. The latter two structures are assumed to contain extended-chain crystallites. By comparison, the melting points and the superheatability of the Instron samples are consistent with the presence of an extended-chain crystal component. The melting of irradiated samples crystallized in the rheometer is also observed to be consistent with this conclusion. In addition, DSC data are compared with the melting points defined with a polarized light microscope equipped with a hot stage.
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  • 28
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 193-200 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Recent literature reports from three laboratories have treated the refraction correction for the Sofica and a noncommercial light scattering photometer. Our re-evaluation of the data contained in these reports, as well as our experiments, indicate that the usually cited n2 refraction correction has not been unquestionably established for these instruments. In some cases, imprecise experimental techniques have been used to support this particular form of the correction. In addition, we find the optical system of the Sofica instrument results in the detector seeing vertically past the horizontal edge of the illuminated volume in violation of a basic assumption in the deduction of the n2 correction. Our experiments, as well as our interpretation of recent literature data, support an exponent of less than 2.0 for the Sofica apparatus, which is consistent with an instrument whose detector views outside the illuminated volume. However, the experimental methods available to evaluate the exponent lack the desired precision.
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  • 29
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 295-305 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Permeability and diffusion coefficients for dimethyl sulfoxide (DMSO) in polyethylene have been measured by the “time-lag” technique and found to be affected by the adsorption of DMSO vapor in the low-pressure side of the apparatus. An analytical method is described for correcting the apparent permeability coefficients for such adsorption effects. “True” permeability coefficients for DMSO in polyethylene, expressed in units of cm3(STP) - cm/(sec-cm2-cmHg), vary from 0.92 X 10-7 at 30°C to 1.7 X 10-7 at 45°C, and their dependence on relative DMSO pressure appears to be small. The energy of activation for the permeation process is 7.1 kcal/mole. The described correction method is also applicable to the permeation of water vapor through polyethylene and poly-(phenylene oxide). The apparent diffusion coefficients could not be corrected by this method. The solubility of DMSO in polyethylene was measured with a Bakr-McBain balance and found to be very small; solubility coefficients are less than 0.8 cm3(STP) DMSO/(cm3 polymer-cmHg). It is concluded that the transport and solution behavior of DMSO in polyethylene is more similar to that of water vapor than to the corresponding behavior of organic vapors.
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  • 30
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 283-293 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The elastic behavior of composite and interpenetrating network structures composed of non-Gaussian chains is investigated. The chain probability density given by Nagai is employed utilizing only the leading correction terms for finite chain extensibility. The independent-network hypothesis, proven valid in Gaussian statistics, is shown to be erroneous in non-Gaussian systems. Further, it is found that composite networks composed of monodisperse chains are elastically isotropic, whereas a most probable contourlength distribution yields a large anisotropy but in the direction opposite to that observed experimentally for rubber. On the other hand, retention of the independent-network hypothesis coupled with a most probable distribution successfully accounts for much of the observed anisotropy. Interpenetrating networks are shown to be substantially anisotropic when a most probable contour-length distribution is employed.
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  • 31
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1167-1170 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
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  • 32
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1175-1177 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 33
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1153-1165 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The anisotropy of the α and β relaxations in oriented poly(ethylene terephthalate) has been studied by dynamic mechanical and dielectric relaxation measurements. The α relaxation shows considerable mechanical anisotropy but gives rise to an isotropic dielectric process. The β relaxation, on the other hand, shows pronounced dielectric anisotropy but very little mechanical anisotropy. The implication of these results with regard to possible interpretations of the relaxations are discussed.
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  • 34
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1171-1174 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 35
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 565-567 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 36
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 575-575 
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    Keywords: Physics ; Polymer and Materials Science
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  • 37
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Electron paramagnetic resonance (EPR) spectroscopy was used to compute the surface bond rupture density in polyurethane and to determine the phase experiencing fracture in styrene-butadiene block copolymers when these elastomers are subjected to mechanical degradation by grinding. The polyurethane grinding was done at temperatures above and below the glass transition Tg; 0.155 × 1013 radicals/cm2 of fracture surface area were formed above the Tg and 4.42 × 1013 radicals/cm2 for grinding below the Tg. These values are essentially equal to those found earlier for spherulitic polymers. In all cases the fracture appears able to progress along preferential paths so as to rupture significantly fewer molecular chains than one would expect on the basis of calculations of the number of chains passing through each square centimeter of cross section. Comparison of EPR spectra formed by grinding styrene-butadiene copolymer with those of styrene and butadiene above indicated that at cryogenic temperature, the fracture in the copolymer takes place in the butadiene phase.
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  • 38
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In the analysis of light scattering data from polymer latex systems or other systems of spherical particles, it is necessary to assume a particle size distribution function. Theoretical angular scattering functions based on the assumed distribution and representing a wide range of size distribution parameters are compared to experimental data in order to obtain a best fit. In previous work, it has been shown that as the polydispersity increases beyond certain limits the uncertainty in the assignment of the size distribution parameters (i.e., the best fit) increases. This report is concerned with the analysis of angular scattering from unimodal systems and simulated cases where theoretical scattering functions for wide, negatively skewed distributions are used as “experimental data,” are analyzed by utilizing four different distribution functions. These functions represent different degrees of skewness and include negatively, positively, and normally skewed distributions. The results from the use of the various distribution functions are discussed with respect to the uncertainly in the assignment of distribution parameters resulting from the loss of structure in the angular scattering pattern due to increased polydispersity. Scattering data from the bimodal distribution are analyzed by assuming a unimodel distribution, and the consequences of this assumption are assessed.
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  • 39
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 693-697 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The characteristic ratios Cof and C∞ are calculated for infinitely long poly(L-amino acid) chains having a—CH2—R′ substitution at the Cα atom, as functions of the valence angle τ at the Cα atom. The value of Cof is found to increase from 1.6 to 2.3 as τ varies from 105 to 115°. On the other hand, C∞ decreases with increasing τ in the range 105-111°, passes through a minimum at 111°, and then increases slowly. Since, C∞ is much less dependent on τ in the most commonly observed range (110-115°), any variation in τ in this range due to solvent would not appreciably affect C∞. The calculated temperature coefficient of C∞ is negative and increases significantly in absolute magnitude even for small deviations in τ from 110°.
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  • 40
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1255-1272 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The influence of annealing processes on the thermal behavior of organic glasses in the glass-transition interval has been investigated and analyzed quantitatively. In detailed annealing studies of atactic polystyrene and Aroclor 5460, the absorption of thermal energy superposed on the increase in the specific heat at the glass transition, observed with suitably chosen heating rates, was followed by the differential thermal method. It is concluded that the absorption of thermal energy observed under these conditions parallels the extent of molecular relaxation that has taken place during the annealing period. It is not necessary to postulate a first-order process to account for the energy absorption. Moreover, such a postulate leads to severe conceptual difficulties regarding the development of crystallinity in crystallizable materials. The areas and the shapes of the endotherms are considered in terms of the original physical properties of the quenched glasses and the anticipated equilibrium properties. Relationships between the extent of energy absorption and time-dependent processes such as volume relaxation are discussed.
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  • 41
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1285-1296 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: As part of a study of chemical and physical changes accompanying the formation of carbons by the pyrolysis of polymers, conventional electron microscopy, electron diffraction, and scanning electron microscopy techniques have been used to examine structural and morphological features of polyacrylonitrile (PAN) crystals, powder, and fibers, and of Saran and poly(vinylidene chloride) (PVDC) powder. Changes accompanying the heating of these polymers in air and in nitrogen have been investigated. PAN crystals grown from propylene carbonate were similar to those obtained by Klement and Geil. When heated in air at 220°C they retained their morphology, and electron diffraction gave the same reflections as PAN. On further heating to 400°C in nitrogen the morphology was retained, but the diffraction was lost. Crystals treated in nitrogen alone at 200°C showed morphology similar to that of the polymer. PAN powders and fibers retained discernable external features of their morphology on heating to 800°C. These results are discussed with reference to changes which take place when poly(vinylidene chloride) and Saran are heated in the range 150-180°C, which results in the loss of one hydrogen chloride per monomer unit, and are subsequently carbonized at 800°C. The development of pore structure and the adsorptive properties of Saran carbons are also discussed.
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  • 42
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 847-856 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The interdependence of the enthalpic contribution A2, H and the entropic contribution A2, s to the second osmotic virial coefficient for a given polymer-solvent system has been investigated from the experimental and the theoretical point of view. Experimentally, the following common facts were observed for various systems at temperatures and pressures below the critical values for the solvent. Both the isobaric and isothermal dependences can be approximated over relatively wide ranges of A2, H by linear relations with a slope deviating only slightly, but in a characteristic manner from a value of -1. When the temperature is increased at constant pressure one moves along an isobar towards higher A2, H; when the pressure is increased at constant temperature, one moves along an isotherm in the opposite direction, i.e., towards lower A2, H. Theoretically this behavior can be described in a qualitative manner, starting from a relation derived by Patterson and Delmas on the basis of the Prigogine corresponding-states theory. The reasons for the lack of quantitative agreement are discussed.
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  • 43
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The method of free torsional vibrations was used to determine the temperature dependence of the storage and loss shear modulus of poly(2-hydroxyethyl methacrylate) samples swollen with ethylene glycol, formamide, n-propanol, and water. The measurements included the glassy region (starting with temperatures from -130 to -190°C) and the main (α) transition from the glassy to the rubberlike state. At a volume fraction of the low molecular weight compound vd 〉 0.2, the above systems exhibit, besides the α dispersion, only the secondary (βSW) dispersion, which is generally attributed to the relaxation motions of the hydroxyethyl groups of the side chains interacting with molecules of the diluent. If no separation of the diluent in a second phase occurs at the measurement temperatures, the temperatures of both dispersions decrease with increasing vd and approach the glass transition temperature of the low molecular weight compound. The concentration dependences of the dispersion temperatures were described by an equation derived elsewhere for the concentration dependence of the glass transition temperature. The results indicate that molecules of the diluent contribute significantly to the intensity of the βSW transition and simultaneously affect its limiting temperatures (for vd = 1 and vd = 0). Specific differences among the systems described above appear only at those temperatures where same of the low molecular weight compound separates into a crystalline or glassy phase.
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  • 44
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1497-1508 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The relative amounts of the α and the γ crystalline forms of nylon 6 obtained from the melt under different crystallization conditions have been studied by an x-ray diffraction procedure by comparison with a calibration curve obtained from the diffraction of standard samples. The weight fraction of the α form decreases with increasing crystallization temperature and that of the γ form increases. Growth of the α form is predominant in crystallization at 100°C and of the α form at 200°C. The amount of the α form tends to increase on annealing at 200°C for specimens crystallized at any temperature.
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  • 45
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1509-1520 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Submicrocracks, free radicals, and endgroups of scissioned molecules formed in polyethylene, polypropylene, and polycaprolactam under uniaxial tension have been investigated. Measurements were carried out by small-angle x-ray scattering, electron paramagnetic resonance, and infrared spectroscopy. The concentration of submicrocracks is almost the same as that of free radicals but is smaller than the concentration of scissioned macromolecules by approximately three orders of magnitude. The number of scissions per crack proved to be close to the number of macromolecules passing through the cross section of a submicrocrack calculated on the assumption of close packing. It is concluded that submicrocracks in stressed polymers are formed as a result of chain reactions of macromolecular decomposition initiated by the active end primary free radicals.
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  • 46
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1481-1495 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It has been shown that sorption equilibrium in the system polymer-mixed solvent and the total sorption as one of its manifestations can be derived from osmotic equilibrium. The equilibrium relation for the dependence of the osmotic pressure II (as the potential for total sorption) on the composition of the ternary polymer-containing phase also includes the preferential sorption ε. This complication leads to difficulties in the analysis of the dependence of II on composition: for this reason, analysis has been limited to the case of a very dilute polymer phase. If preferential sorption is neglected, the occurrence of an extremum on the curve representing the dependence of the total sorption on the composition of the mixed solvent is affected by the Flory-Huggins parameters as in the occurrence of an inversion in preferential sorption, with the exception that in the former case the difference in the molar volumes of the solvent components contributes a term smaller by a factor of two. In the general case, however, the contribution of preferential sorption to the osmotic pressure (which has always a negative sign) also plays its role. Consequently, while total sorption, at a low preferential sorption and at a large positive value of the solvent-solvent interaction parameter χ12, can exhibit a maximum, a larger preferential sorption can overcompensate the effect of the parameter χ12, so that a minimum appears. The coexistence of a minimum with a maximum on the same curve is possible in some cases with positive χ12. The latter theoretical predictions have not yet been confirmed experimentally. At a negative χ12 the extremum is always a minimum.
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  • 47
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1521-1527 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Stress and birefringence relaxation have been measured for two polyurethane block polymers at several temperatures to 140°C. Superposition of the stress curves is possible, but the existence of multiple relaxation mechanisms makes such a process of questionable validity. Simple superposition of the birefringence relaxation was not possible. The time and temperature dependence of the stress-optical coefficient implies different mechanisms for mechanical and optical relaxation process. Analysis of the birefringence data requires consideration of nonorientational sources of birefringence.
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  • 48
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1529-1535 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The lattice-theory equations for the surface tensions of polymer solutions based on the parallel-layer model have been tested for three-component systems. Surface tensions of solutions of some low molecular weight polyisobutylenes and polydimethylsiloxanes in n-heptane-tetralin mixtures and solutions of mixtures of the polymers in these solvents were measured at room temperature. The results are in good agreement with the theoretical calculations.
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  • 49
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1467-1480 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Osmotic and sorption equilibria in the system polymer-binary solvent can be represented with advantage in coordinates (u1, v3), where v3 is the volume fraction of the polymer and u1 gives the composition (volume fraction) of the binary solvent in the polymer phase. The coexistence lines and osmotic isobars are plotted; the former are used to read the preferential sorption ε of one of the solvent components in the polymer. The newly formulated equilibrium condition for the preferential sorption is applied to the Flory-Huggins theory extended by the ternary interaction parameter χT. This is used as a starting point for analyzing the conditions under which inversion of preferential sorption takes place, i.e., the sign of ε changes. The existence of inversion and the course of the inversion line in the v3 versus u1 plot are affected in a decisive manner by the extent to which the effect of the mutual interaction of solvent components prevails over the effect of the relative difference between their molar volumes and of the difference in strength of their interaction with the polymer. The effect of the ratio of molar volumes upon the preferential sorption increases with the concentration of the polymer, so that for v3 not too far from unity the component having the smaller molecule is necessarily sorbed preferentially. If, therefore, both types of small molecules are not of the same size, the inversion vanishes for large v3 even in systems where it actually occurs if v3 is small. On the contrary, the same effect can in other cases have as its consequence an inversion at moderate values of v3, even if it does not appear as v3 approaches zero; a similar effect can also be produced by a nonzero value of the interaction parameter χT. The neighborhood of the inversion line can have a “divergent” or a “convergent” character, depending on whether the component being preferentially sorbed is that present in excess. The former case is observed with negative and the latter for the positive values of the binary solvent-solvent interaction parameter χ12. The inversion with the divergent neighborhood has not yet been confirmed experimentally, owing to the small number of systems investigated.
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  • 50
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 253-264 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of iodine sorption on the small-angle x-ray diffraction intensity is discussed in terms of the distribution of iodine sorbed in the amorphous regions of polymers. The change in the intensity of the peak corresponding to long periods is measured as a function of the iodine uptake in drawn, and annealed poly(ethylene terephthalate) films. A linear relation with slope K is observed between the square root of relative intensity and iodine uptake. The slope K varies with annealing conditions. Theoretical values calculated for models of the distribution of iodine in amorphous regions, are compared with the observed K. Results can be interpreted on the basis of a “concave” distribution of iodine, i.e., with sorption sites more numerous near a crystal surface than in the interior of an amorphous region.
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  • 51
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 323-337 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Glass transition temperatures were determined for a homologous series of unsubstituted lactone monomers varying in ring size from four to sixteen atoms. Examination of these transitions as a function of ring size shows a maximum in Tg for the seven-atom ε-caproalctone ring. This behavior is interpreted on the basis of a conformational change in lactones which occurs in rings containing seven to nine atoms. The Tg values of polylactones derived from these cyclic esters were determined and correlated with Tg values of the monomers. Except for the anomolous ε-caprolactone and the strained fourmembered lactone, an apparently constant difference between monomer and polymer Tg is observed. Treatment of the polylactones as methylene copolymers permits extrapolations of the Tg values to obtain that of polyethylene. Two values suggesting the γ and β transitions of polyethylene are obtained.
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  • 52
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 369-373 
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 53
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 433-448 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements are reported for the dielectric loss factor of the SCMC solutions over the frequency range 2 MHz to 50 MHz as a function of concentration of SCMC, concentration of added sodium chloride, molecular weight, and temperature. The results are in general agreement with those of other workers and are interpreted in terms of ionic theories in which motion of the diffuse counterions is the dominant feature.
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  • 54
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 507-517 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new typical orientation pattern of polyethylene has been observed in extruded, melt-drawn composites containing 10% polyethylene and 90% polystyrene. In these composites, the polyethylene phase is dispersed in the polystyrene matrix as thin, long ribbons (width 1000 Å, thickness 500 Å). The b axis of the crystallites is found oriented preferentially along the long dimension of the ribbons, i.e., in the extrusion direction. The a and c axes of the crystallites show no preferred orientation. This texture pattern is attributed to the fact that, in view of the small cross section of the polyethylene phase, crystallization can proceed only along the long axis of the ribbons. Since the b axis is the direction of fastest growth in polyethylene (and the radial direction in a spherulite), most polyethylene unit cells are oriented with their b axes in the long dimension of the ribbons.
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  • 55
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 489-497 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Proton spin-lattice relaxation times of solvent molecules were measured on ternary mixtures of a polymer and two solvents by the adiabatic rapid-passage method. The selective adsorption of a good solvent was verified by this experimental technique for the systems benzene - cyclohexane - polystyrene(PS), benzene - carbon tetrachloride - poly(methyl methacrylate)(PMMA), and chloroform - carbon tetrachloride - PMMA. The number of molecules of adsorbed benzene per monomeric unit of PS was estimated to be about four, which is almost identical with that determined previously by thermodynamic measurements. The number of molecules of benzene and chloroform adsorbed on PMMA were also determined to be about five and four, respectively. It was found that the interaction between chloroform and PMMA has the greatest effect on the molecular motion of the solvent, whereas the benzene - PS interaction is weak.
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1611-1613 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 57
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1575-1585 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Young's modulus and mechanical damping of 15 organic liquids in polystyrene have been measured from 4°K to 250°K. The concentration was generally in the range from 10 to 15%, but the polystyrene-toluene system was investigated over the range from 0 to 16%. Some liquids cause the 40°K damping peak of polystyrene to disappear, other liquids do not. Seven of the liquids which cause the disappearance of the 40°K peak give rise to new large damping peaks at the temperature expected for the secondary glass transition temperatures of the liquids, that is, at 0.77 Tg of the liquids. Some of the liquids produced large unexplained damping peaks at temperatures above the expected glass transition temperatures Tg of the liquids. It is suggested that the γ peak in polystyrene is caused by styrene monomer.
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  • 58
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1615-1619 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
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  • 59
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1621-1624 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
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  • 60
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1625-1629 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 61
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1639-1655 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The viscoelastic (VE) response of freeze-dried blends of polystyrene (PS) and poly-(2,6-dimethyl phenylene oxide) (PPO) has been studied as a function of composition, frequency, and temperature to examine the degree of rheological compatibility. When blended together, the relaxation processes of both molecular species exhibit the same temperature dependence. However, the temperature dependence of the VE response is a function of composition. It is shown that this behavior can be predicted from the measured glass transition temperatures by assuming the additivity of the free volumes of the components. The properties of the blends are compared at equal free volumes. The effective segmental friction factor is found to be independent of composition while the modulus of the rubbery plateau increases with PPO concentration. This result is interpreted as a change in the entanglement molecular weight Me of the blends. When the changes in Me are considered, the relationship between the zero-shear viscosity η0 and the 3.4 power of the weight-average molecular weight, commonly found for high molecular weight homopolymers, predicts the compositional dependence of η0 for the PPO-PS blends. It is concluded that the PPO-PS system forms a rheologically compatible blend.
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  • 62
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1631-1637 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The results of bulk modulus and density measurements on low-density polyethylene to 30 kbar are presented. From these data the pressure coefficient dTt/dp of the glass transition temperature is obtained, and a comparison is made with data calculated from Pastine's theoretical equation of state for polyethylene.
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  • 63
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 685-691 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The change in x-ray diffraction intensity with time following rapid stretching by various amounts is measured for a low-density polyethylene sample at several temperatures. An appreciable decrease in intensity with time at the meridian of the diffraction from the 110 and 200 planes is observed to occur within the first 5 sec following stretching. The change takes considerably longer times at lower temperatures. By use of a calibration curve, the change in crystal orientation functions for the a, b, and c crystal axes were calculated, and an increase in c-axis orientation was shown. From the results of birerringence measurements on the same sample, the crystalline and amorphous contributions to birefringence were calculated. It was shown that stretching is initially accompanied by a greater amount of amorphous than crystalline orientation, and that relaxation involves an increase in crystalline orientation accompanied by a decrease in amorphous orientation.
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  • 64
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 741-745 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Commercial and fractionated samples of poly(ethylene glycol) and a sample of Dextran were used as standards to show the limitation of a cellulose acetate membrane for osmotic pressure determination of molecular weight in an aqueous system. The leakage of this membrane was much greater in the aqueous system than in organic solvents.
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  • 65
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 761-765 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 5 Ill.
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  • 66
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    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 781-810 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The mechanical properties of poly(ethylene terephthalate) are examined to see if the quantitative morphological criteria previously used to define the structural state of isotactic polypropylene will lead to similar quantitative structure-property correlations when applied to PET. Tenacity, thermal shrinkage in oil and air, tensile modulus, dynamic loss modulus, long spacings, and small-angle x-ray intensities are included in the study. All of the data were obtained from the open literature. In all cases the physical properties correlate simply and quantitatively with the internal structure of the PET, and the character of the correlations leads to new insights into the nature of the internal mechanisms controlling the observed properties. The study shows that only by considering the structural state of a polymer, and not its fabrication parameters, can general, simplifying, quantitative, structure-property correlations be achieved.
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  • 67
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A mathematical treatment is presented for the gel-permeation chromatographic and intrinsic viscosity behavior of randomly crosslinked polymers having primary molecular weight distributions of the Schulz-Zimm form. Kimura's serial solution of the integro-differential equation derived by Saito for randomly crosslinked polymers is employed for the distribution function. The intrinsic viscosity of a molecule containing i crosslinks is assumed related to that of a linear molecule of the same number of units through [η]br/ = gi½[η]l where gi = (Rbr2)i/Rl2 = {[1 + (i/6)]½ + (4i/3π)}-½. Rbrand Rl denoting the root-mean-square radii of gyration of branched and linear chains of the same mass. It is also assumed that GPC elution is controlled by the hydrodynamic volumes of the molecules. Representative calculation results are displayed for polymers with a narrow primary distribution and the “most probable” primary distribution. Results for the latter polymers are compared with those previously obtained by a somewhat different mathematical approach.
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  • 68
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    Biological Mass Spectrometry 6 (1972), S. 33-37 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of the seven isomeric methylindoles were recorded and the [metastable ion]/[daughter ion] ratios for the reactions m/e 130 → m/e 103 and m/e 103 → m/e 77 have been obtained. The ratios indicate that the decomposing [M  -  1] ions (m/e 130) from the 4, 5, 6 and 7 isomers are energetically similar as are the [M  -  1] ions from the 2 and 3 isomers. The results observed for the m/e → 103 m/e 77 reaction showed that the decomposing m/e 103 ions from the 2, 3, 4, 5, 6 and 7 isomers all have the same energy distribution. N-Methylindole gave ratios which were similar to the 4 to 7 isomers at 70eV but different at 20 eV. The ion kinetic energy (IKE) spectra of all the isomeric methylindoles were also obtained and the results compared with the data obtained from the [metastable ion]/[daughter ion] approach. The results from the IKE spectra indicated that the energy distributions of the [M  -  1] and [(M  -  1)  -  HCN] ions from 1-methylindole and the [(M  -  1)  -  HCN] ions from 2-methylindole could readily be distinguished from other isomers whose [metastable ion]/[daughter ion] ratios were similar. Thus by using both techniques certain ambiguities can be resolved.
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  • 69
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complete low resolution mass spectra and some high resolution data are presented and discussed for a series of naturally occurring 14β-hydroxy bufadienolides (toad venoms) and their derivatives, but excluding compounds with a 14β,15β-epoxy group. The bufadienolides employed were bufalin, bufotalin, gamabufotalin, telocinobufagin, arenobufagin, 3β-acetoxybufotalien, 3β-acetoxyhellebrigenin, 3β-acetoxybufalin, 3-ketobufalin, 14-anhydrobufalin, 3β-acetoxy-15-ketobufalin and 15α-hydroxybufalin. The relatively unsaturated 2-pyrone functionality at C-17β has been used as an integral label to distinguish (from elemental composition data) ions containing it, from those coming from other parts of the molecule that do not. Structural ‘ion types’ are proposed to interpret this spectral data, and the prognosis for structure elucidation of other bufadienolides by high resolution mass spectrometry appears good.
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  • 70
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    Biological Mass Spectrometry 6 (1972), S. 1-8 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass spectrometry can be used for amino acid sequence determination in β-lysine-containing peptides and for the identification of α- and β-lysine residues in peptides, as well as for amide bond type determination in β-lysine peptides. The peptide bond in streptothricin D is shown to be formed through the participation of an ε-amino group of the L-β-lysine residue.
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  • 71
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    Biological Mass Spectrometry 6 (1972), S. 39-45 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of a number of methyl- and phenylthiohydantoin amino acid derivatives have been obtained. The major metastable transitions occurring in the mass spectra of these derivatives have been identified and measured. The major fragmentation pathways associated with the metastable transitions have been outlined and are discussed for each group of compounds. Inspection of the metastable data has shown that there is at least one unique metastable transition occurring for each thiohydantoin derivative which may be used to uniquely identify that derivative in the presence of a mixture of thiohydantoin derivatives obtained from the Edman degradation of a peptide or protein. The use of metastable ions to uniquely identify thiohydantoin derivatives in mixtures has proven useful in the identification of the MTH and PTH derivatives of glycine whose molecular ions are not unique and for resolving such ambiguities as occur for example in the mixture of leucine and isoleucine.
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  • 72
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of several perfluoroaromatic nitrogen compounds, including primary and secondary amines, diamines, nitriles, hydrazines, azines and azo compounds, are presented. Fragmentation patterns of these compounds are described and the data are discussed in terms of comparisons amongst perfluoroaromatic nitrogen compounds, and with reference to the hydrogen substituted analogs, or to oxygen and sulfur analogs of a particular compound.
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  • 73
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    Biological Mass Spectrometry 6 (1972) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 74
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    Biological Mass Spectrometry 6 (1972), S. 151-166 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron-impact induced fragmentation of staphylomycin S (I) and related cyclodepsipeptides (II to V) is mainly initiated by elimination of an azomethin molecule (R—CH=N—R′), i.e. 1,2-dehydro-4-oxopiperidine for I and II, 1,2-dehydro-4-hydroxy-piperidine for III and IV, and an unknown hydroxy-1,2-dehydro-4-oxopiperidine for VI. Cyclic imino acids, e.g. a pipecolic acid derivative for I to IV and 4-hydroxyproline for etamycin (IX) preferentially trigger this reaction. Clearcut evidence for the amino acid sequence is given by the mass spectra of the linear peptides obtained from I, V and IX by alkaline hydrolysis of the lactone function and esterification of the carboxy group.
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  • 75
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Charge exchange and electron-impact induced cleavages of some N-phenyl benzamides, phenyl benzoates and benzophenones are reported. The data obtained appear to be consistent with energy being lost from ions by photon emission or stored in isolated states of the molecular ions.
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  • 76
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    Biological Mass Spectrometry 6 (1972) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 77
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: It is shown that in general it is not possible to differentiate between diphenyl methane derivatives (and compounds of analogous structure) substituted in o-position to the CH2-bridge and those carrying an m- or p-substituent by resorting solely to the ‘ortho-effect’ of the former. A rationale for this apparent anomaly is given.
    Notes: Es ist i.a. nicht möglich, zwischen Diphenylmethan-Derivaten (und analogen Verbindungen), die in o-Stellung zur CH2-Brücke substituiert sind, und inren m- und P-Isomeren nur auf Grund des ‘ortho-Effektes’ zu unterscheiden. Eine Erklärung für dieses scheinbar anomale Verhalten wird gegeben.
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    Biological Mass Spectrometry 6 (1972), S. 293-300 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectral fragmentations of several naturally-occurring 3,4-dialkoxy furocoumarins from the Halfordia species and their nor-derivatives have been studied using deuterium labelling and metastable analysis. Halfordin (I), isohalfordin (VI) and halkendin (X) show a common major breakdown pathway involving initial loss of a methyl radical from the 3-methoxy group followed by expulsion of CO, then loss of C2H3O, the latter fragment containing the methyl group from the 4-position.
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    Biological Mass Spectrometry 6 (1972), S. 341-343 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 80
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The mass spectrum of N,N′,N″-triacetyl spermidine (I) is characterised by signals at m/e 143, 157 and 169. The degradation reactions which lead to the corresponding ions cannot be explained by known sequences. By examination of the mass spectra of derivatives of I, fragmentation mechanisms have been deduced.It is interesting to note that it is mainly the 1,3-diamino propane part of the spermidine molecule which participates in the mass spectral degradation to give the previously mentioned, characteristic ions.The two tertiary nitrogen atoms of the diamino propane part are the main promoters of these fragmentation reactions, as can be seen Schemes 2 to 7. Hence the mode of mass spectral degradation of the trifunctional spermidine derivative proceeds in a similar way to that of the bifunctional alkanes.
    Notes: Das Massenspektrum von N,N′,N″-Triacetylspermidin (I) zeichnet sich durch charakteristische Signale bei m/e 143, 157 und 169 aus. De Reaktionen, die zu den entsprecenden Ionen führen, lassen sich nicht durch Anweding einfacher Fragmentierungsreaktionen erklären. Auf der Bzasis der Massenspektren deuterierter Derivate von I werden Fragmentierungsmechanismen vorgeschlagen. Interessanterweise ist hauptsächlich der 1, 3-Diaminopropan-Teil und weiniger der 1, 4-Diamino-butan-Teil (Putrescin) des Spermidin-Moleküls an den Abbaureaktionen zu den erwänten Ionen beteilligt. Die beiden teriären Sticktoffatome des Diaminopropanteiles sind im wesentlichen die Promotoren der Fragmentierung, wie aus den Schematatas 2 bis 7 hervorgeht. Dieser Verlauf des massenspektrometrischen Zerfalls des trifunktionellen Spermidin-Derivates verläuft ser ähnlich dem Zerfall bifunktioneller Alkane.
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    Biological Mass Spectrometry 6 (1972), S. 425-427 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of two silanes and two cyclic siloxanes of the general formulae HSi(CH3)2-C6H4—(CF2)n—C6H4(CH3)2SiH and (n = 2 and 3) are reported and discussed. Although some major differences are apparent between the spectra of the two silanes, the fragmentation patterns of the cyclic siloxanes are largely identical.
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    Biological Mass Spectrometry 6 (1972), S. 549-557 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The fragmentation mechanisms of the six isomeric cyclohexene-1,2-dicarboxylic acids are discussed. Only the 1-cyclohexene acid, by virtue of the major sequential losses of H2O and CO2 from the molecular ion, is readily distinguishable from its isomers, all of whose mass spectra are closely similar. In contrast to cis and trans cyclohexane-1,2-dicarboxylic acids, whose mass spectra were markedly different, the cis and trans cyclohexene-1,2-dicarboxylic acids fragment in a similar fashion. The mass spectra of 1-cyclopentene-1,2-dicarboxylic acid and 1-cyclobutene-1,2-dicarboxylic acid also exhibit a strong carboxyl-carboxyl interaction; the fragmentation behaviour of the 1-cyclopenteneacid is, however, more complex than that of the 1-cyclohexene and 1-cyclobutene acids.
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    Biological Mass Spectrometry 6 (1972), S. 601-601 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 84
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complete low resolution mass spectra and high resolution data for selected important peaks are presented and discussed for a series of naturally occurring 14β, 15β-epoxybufadienolides (toad poisons) and their derivatives. The compounds examined were resibufogenin, marinobufagin, cinobufagin, desacetylcinobufagin, cinobufotalin, desacetylcinobufotalin and resibufagin, and the derivatives were 11α-hydroxyresibufogenin, 3β-acetoxymarinobufagin, 3-ketocinobufagin, 3β-acetoxy-16β-desacetylcinobufagin, 3β-acetoxy-16-ketocinobufagin, resibufaginol, 14α-artebufogenin and 3β-suberyloxyresibufogenin methyl ester. The relatively unsaturated 2-pyrone group of C-17β has been used as an integral label to distinguish (from elemental composition data) ions containing it from those arising in other parts of the molecule that do not, and the spectra are interpreted in terms of structural ‘ion types’.
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  • 85
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Mass spectra of some 1,3-cyclopentanediones and 1,2,4-cyclopentanetriones, related to compounds encountered in the chemistry of hops bitter constituents have been determined. Methyl substituted compounds mostly show ring degradation, while for longer alkyl groups and acyl groups, fragmentations in the side chain carry most of the total ionization. When both alkyl (〉 2C) and acyl substituents are present, fragmentations in the alkyl group always occur before those in the acyl side chain. The observed degradation processes are useful for the interpretation of the spectra of hop bitter acids and derived products.
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    Biological Mass Spectrometry 6 (1972), S. 949-952 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of dimethyl ketal derivatives of cyclohexanone and the 2-, 3- and 4-methylcyclohexanones are discussed relative to their usefulness in indicating the point of alkyl substitution. Major fragments in the spectra (m/e 101 and m/e 115) arise by α-cleavage, hydrogen rearrangement and further cleavage to give even-electron species. The spectra yield structural information equivalent to that obtained from the corresponding ethylene ketals. The ease of preparation of dimethyl ketals and the mildness of reaction conditions relative to ethylene ketals warrant further exploitation of dimethyl ketals as fragmentation-directing derivatives in mass spectrometry.
    Type of Medium: Electronic Resource
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  • 87
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1972), S. 953-962 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of the trimethylsilyl derivatives of several steroids containing a 16-hydroxy function are presented. The mechanisms giving rise to various characteristic fragment ions were investigated with the aid of deuterium and 18O-labeling.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 88
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1972), S. 991-1001 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation and the mass spectra of the trimethylsilyl ethers of six hydroxyporphyrins are reported. In every case the side chain bearing the ether grouping is the most labile on electron-impact and exhibits characteristic ‘benzylic’ cleavage. The presence of a metastable peak allows a definite identification of this cleavage to be made.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 89
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1972), S. 909-916 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fragmentation of the dimethylsilyl (DMS) derivative of methyl 12-hydroxyoctadecanoate is found to be closely analogous to that of the previously studied trimethylsilyl (TMS) derivative, including migration of the silyl substituent from C-12 to the ester carboxyl function. besides establishing comparable migratory aptitudes of the TMS and DMS substituents, details of several other processes were revealed by use of deuterium labelling of selected positions and compared with related fragmentation of simple long-chain alcanoic esters.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 90
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 91
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1972), S. 963-970 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ratio [M — D]/{[M-D] + [M — H]} in the 70 eV mass spectra of six deuterated 3-methylthiophenes has been determined. From these values the mole fractions of the molecular ions that lose hydrogen atoms specifically from the various positions of the molecule were calculated, as well as the mole fraction in which the hydrogen atoms are fully scrambled before hydrogen elimination. It appears that hydrogen atoms are mainly lost from a fully scrambled [C5H6S]+· ion and from the α-position of the original molecular ion. A deuterium isotope effect of 1·60 to 1·72 was calculated for the hydrogen elimination. The reaction was also studied at low electron energies. In order to determine the degree of scrambling in the [C5H5S]+ ions, some decomposition reactions of this ion were investigated.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
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  • 92
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1972), S. 1003-1009 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A study of the [M — methyl]+ ion in the mass spectra of ring-deuterated tri- and tetramethylbenzenes has confirmed the partial randomisation of hydrogen and deuterium atoms observed by other workers. The results can be explained by postulating randomisation of the peripheral entities, followed by several cycles of ring expansion and contraction, prior to fragmentation.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
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  • 93
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    Biological Mass Spectrometry 6 (1972), S. 1347-1351 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron-impact induced fragmentation of 3,5-diphenyl-1,2,4-oxadiazole has been investigated by labelling experiments, defocused metastable ion detections and high resolution mass measurements. The main fragmentation process suggests heterocyclic cleavage at the 1 to 5 and 3 to 4 bonds confirming our previous interpretation. The structure of the major fragment ion [C7H5NO]+· has been interpreted as being represented by the isomeric benzonitrile oxide and phenylisocyanate structures, the latter isomerising irreversibly from the former. The benzonitrile oxide structure is consistent with [C7H5NO]+· formation by cleavage of the 1 to 5 and 3 to 4 bonds.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 94
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Elimination of ketene from the molecular ion of p-chloroacetanilide takes place via a 4-membered transition state, as evidenced by deuterium isotope effects on competing metastable transitions.
    Additional Material: 2 Tab.
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  • 95
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1972), S. 273-282 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ion kinetic energy (IKE) spectra of pyrazine, pyrimidine, pyridazine, pyrazine-d4, pyrimidine-d4 and pyridazine-d4 have shown that these compounds can more readily be distinguished on the basis of IKE spectra than mass spectra. Studies of the fragmentation of various doublycharged ions have given information about the localization of charge on the heteroatoms and on the structures of the ions themselves. Transition states from which fragmentation occurs for doublycharged ions with loss of either [H]+ or [D]+ have shown large differences of the order 1 Å between the intercharge distances in the two cases.
    Additional Material: 3 Ill.
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  • 96
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1972), S. i 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstracts.
    Type of Medium: Electronic Resource
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  • 97
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1972), S. 345-346 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of cyclic fluoroethers of the general formula (n = 1 to 4) are reported and discussed. Although these spectra show many similar features, those for which n = 3 and 4 contain intense peaks at m/e 63 which are only of relatively low intensity in the spectra of the other two.A similarity between the electron-impact and thermal fragmentation patterns of these compounds is noted.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 98
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1972), S. 349-366 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The results of a mass spectrometric analysis of the series C6Cl6; C6Cl5F; 1,3-F2C6Cl4; 1,3,5-F3C6Cl3; 1,2,3,5-F4C6Cl2; C6F5Cl; C6F6 obtained by successive replacements of chlorine atoms by fluorine atoms, starting with hexachlorobenzene, are presented. Similarly the corresponding series of perfluorochloropyridines are examined. The sequences of degradation observed are quite regular in both series, and correspond to possible simple mechanisms often confirmed by the observations of the corresponding metastable ions.
    Notes: Nous présentons ici les résultats de l'analyse en spectrométrie de maasse des séries C6Cl6; C6Cl5F; 1,3-F4C6Cl2; C6F5Cl; C6F6 obstenues par remplacvement successif des atomes de chlore par des atomes de flour, à partir de l'hexachlorobenzène. De měme, la série correspondante des perchloroflouropyridines est analysée. Les séquences de dégradations observées sont trés réguliéres dans les deux séries, et sont interprétables par des schémas simples, souvent confirmés par l'observation des pics métastables correspondents.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 99
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The expulsion of CH3· from the [M — C2H4]+· ion of butyrophenone occurs with loss of a ring hydrogen and the methylene group as evidenced by deuterium labeling and metastable transitions.
    Type of Medium: Electronic Resource
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  • 100
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 1-9 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It has been shown in this investigation that the permeation of propane and propylene through polyethylene membranes exhibit a generalized behavior in the vicinity of the condensation point of the penetrant. Correlations to evaluate the permeation flux are presented.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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