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  • Physics  (2)
  • poly(ethylene terephthalate)  (2)
  • Analytical Chemistry and Spectroscopy  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Importance of quality control in a gas chromatographic method to characterize crude oilsMany of the details in this paper were presented as a poster at the Tenth International Symposium on Capillary Chromatography, Riva del Garda, Italy, May 22-25, 1989. (1994)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 463-468 
    Details
    ISSN: 0935-6304
    Keywords: Capillary GC ; Petroleum crude oil ; Condensates ; Carbon number distribution ; Pseudocomponents ; Quality control ; Quality assurance ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A quality control scheme has been developed to achieve reproducible capillary GC characterization of crude oils and petroleum condensates. The method uses an internal standard to quantify the amount of non-eluted material in the crude oil sample. Correlation between the gas chromatographic results and actual distillation was 2 %. After repeated use, however, weekly analysis of the same standard crude oil did not give the correct composition. This was a result of discrimination, which worsened with time, as a result of leaks in the septum or the graphite ferrules. More reproducible results were obtained by performing frequent analyses of quality control samples to ensure that the gas chromatographic system was operating properly. The use of quality control charts was a convenient way of ensuring correct operation and identifying the need for corrective action on the gas chromatographic system.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240170613
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Terminal relaxation and diffusion of entangled three-arm star polymers: Temperature and molecular weight dependencies (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 2503-2510 
    Details
    ISSN: 0887-6266
    Keywords: rheology ; diffusion ; star-branched polymers ; polyisoprene ; terminal viscosity ; molecular weight dependence ; temperature dependence ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Recent experimental investigation of the terminal relaxation in high molecular weight polyisoprenes by dynamic mechanical measurements (C. A. Bero and C.M. Roland, Macromolecules, 29, 1562 (1996)) has found the terminal relaxation times to be more sensitive to changes in temperature for three-arm stars than for the linear polyisoprenes. Moreover, these measurements, carried out with significantly higher molecular weight samples than heretofore, show that the molecular weight dependence of the terminal relaxation times for three-arm star polyisoprenes is much weaker than the exponential dependence previously proposed (L. J. Fetters, et al., Macromolecules, 26, 647 (1993)). Tracer diffusion of labeled linear and three-arm star polyethylene-like diffusant molecules in a highly entangled linear polyethylene matrix exhibit temperature and molecular weight dependencies similar to those observed spectroscopically from bulk polymers. Both the temperature and molecular weight dependencies for the star-branched polymers are at variance with the predictions of the reptation model. It is shown here, however, that these observations can be reconciled through application of the coupling model of relaxation. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2503-2510, 1997
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    The amorphous phase in high-speed spun PET fibers (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 1339-1345 
    Details
    ISSN: 0887-6266
    Keywords: poly(ethylene terephthalate) ; series-parallel model ; series-aggregate model ; high-speed spinning ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two phenomenogical descriptions of oriented semicrystalline polymers, the series-parallel model and the series-aggregate model, were applied to poly(ethylene terephthalate) (PET) fibers obtained at different spinning speeds. The mechanical behavior of the fibers conformed well to both models. The analyses indicate that PET fibers obtained by high-speed spinning possess a more compliant interfibrillar amorphous phase. This feature may account for both the greater dimensional stability, as well as the more reversible mechanical behavior, exhibited by high-speed spun PET. © 1993 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1993.090311009
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  • 4
    Electronic Resource
    Electronic Resource
    Transverse heterogeneity in PET fibers (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 1331-1337 
    Details
    ISSN: 0887-6266
    Keywords: poly(ethylene terephthalate) ; transverse heterogeneity ; crystallinity ; high speed spinning ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: X-ray scattering from a series of poly(ethylene terephthalate) (PET) fibers spun at differet speeds is analyzed to probe the morphology in the direction transverse to the fiber axis. Both the apparent crystal modulus, determined from the change in wide-angle X-ray scattering angle with fiber stretching, and the transverse degree of crystallinity indicate there is a substantial interfiberillar amorphous content. In the PET fiber spun at conventional speeds, only roughly one-quarter of the fiber cross-section is actually occupied by fibrils. The transverse crystallinity increases for fibers spun at speeds sufficient to cause crystallization in the spin line. The X-ray moduli and fibril diameters are correspondingly larger in these high speed spun fibers. © 1993 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1993.090311008
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  • 5
    Electronic Resource
    Electronic Resource
    Shear-induced coalescence in two-phase polymeric systems. I. Determination from small-angle neutron scattering measurements (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 22 (1984), S. 79-93 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It has been found that flow-induced coalescence occurs at a very rapid rate during the mixing of polymeric fluids. Furthermore, the rheological properties of the dispersed and continuous phases, as well as the nature of the flow field used in their blending, can greatly influence this coalescence. The significance of these findings is that in the development of a mixing scheme to obtain a desired morphology with minimum expenditure of time or energy, attention is usually focused only on the particle breakup aspects of the blending process. The competing coalescence can, however, be accelerated by the same conditions often employed to facilitate particle breakup (e.g., higher shear rates, reduced dispersed-phase viscosity).A better understanding of the mechanism for coalescence of viscoelastic fluids is clearly required. In this manner optimal blending of immiscible polymers can be achieved with respect to both the nature of the final material and the ease with which it is obtained.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.180220108
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    Paper (German National Licenses)
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