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  • Polymer and Materials Science  (11)
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  • 1
    Electronic Resource
    Electronic Resource
    ESR study of the initial reaction of the photodegradation of nylon 6 (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 401-410 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The free radicals formed on irradiation of nylon 6 have been studied by means of electron spin resonance (ESR). The irradiation was performed at liquid nitrogen temperature with wavelengths in the region of solar radiation. The spectrum so obtained could best be fitted by assuming —CH2—ĊH—CH2— and —CH2—Ċ=O to be the trapped radicals. The assignment of the spectrum supports the idea that the first step in photodegradation is the breaking of the amide bond. The splitting constant of the α proton of the alkyl radical has been found to be nearly the same for drawn and undrawn yarn. This strongly suggests that the low-energy radiation is capable of breaking bonds only in the unoriented amorphous regions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080306
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  • 2
    Electronic Resource
    Electronic Resource
    The effect of spinning speed and drawing temperature on structure and properties of poly(ethylene terephthalate) yarns (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 37 (1989), S. 595-616 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: From an industrial point of view, it is effective to have a relation between process conditions and resulting product properties. In practice there are many possible process conditions, whereas properties are generally interrelated in a complex way. Thus, there is a strong need for a physical understanding of the product properties in terms of process settings. This comprehension should also allow one to predict possible consequences for the properties when new process conditions become available. To obtain that physical understanding for the development of production processes of PET yarns, use has been made of a simple two-phase model of crystalline and amorphous regions. As process parameters the spinning speed and the drawing temperature were chosen. As the drawing temperatures are only known as machine-setting values, they are simply referred to as “low” and “high.” As mechanical properties the shrinkage, modulus, tenacity, and dynamic mechanical behavior are discussed.
    Additional Material: 24 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1989.070370302
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  • 3
    Electronic Resource
    Electronic Resource
    Molecular changes of PET yarns during stretching measured with rheo-optical infrared spectroscopy and other techniques (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 925-934 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A method has been developed for measuring infrared spectra during the mechanical deformation of yarns. This rheooptical technique was applied to study the molecular processes that take place along the stress-strain curve of PET yarns. The results were combined with data obtained from size exclusion chromatography (SEC) and tensile measurements at elevated temperatures. The results indicate that the first modulus maximum marks the breakdown of the amorphous entanglement network and the start of molecular uncolling by gauche → trans transitions. In addition, stress develops on the crystals and particularly on tie molecules with a short contour length in the amorphous domains. Ultimately, molecular fracture of taut-tie molecules causes the modulus to pass through a second maximum. The chain ends of broken molecules recoil by trans → gauche transitions. Local stress accumulation will lead eventually to yarn rupture. © 1993 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070490518
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  • 4
    Electronic Resource
    Electronic Resource
    Experimental relations between physical structure and mechanical properties of a huge number of drawn poly(ethylene terephthalate) yarns (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 45 (1992), S. 1649-1660 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The results of a study of the relation between a number of mechanical properties of poly(ethylene terephthalate) (PET) yarns and their physical structure are presented. The relation was studied on a set of 295 drawn yarn samples, resulting from an exceptionally large variety in process conditions applied. The size of this experiment offered a unique opportunity to study the property-structure relation more extensively than ever before. Therefore, our understanding of the mechanical properties could be enriched with several new insights. A selection of seven yarn properties has been investigated. Five of them have been derived from the stress-strain curves and the remaining two are shrinkage and shrinkage force. The physical structure has been described with a set of five, statistically selected, parameters. Most of the yarn properties could very well be described in terms of these structure parameters. This description was performed by means of an artificial neural network, ANN. The type of calculation is completely naive, i.e., without any specific mathematical formulation for the relation concerned. The fitting results have been translated into physical aspects related to the well-known molecular two-phase model. The practical importance of a good physical understanding of yarn properties is that the essential possibilities and impossibilities of combinations of properties can far more easily be surveyed and understood. As a result, the efficiency of process developments can be substantially improved.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070450916
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of winding speed, drawing and heating on the crystalline structure of nylon 6 yarns (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 26 (1981), S. 713-732 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Nylon 6 yarns were wound at speeds varying from 700 to 5500 mpm. The effect of the winding speed on both α- and γ-type crystals in these undrawn yarns was studied. Also the effects of dry heat, tension, and heating in saturated steam were included in this investigation, since they provide useful information for drawing and heat-setting processes. The emphasis was put on the characterization of the crystalline part of the yarns. By applying recently developed techniques, relative amounts of the two crystalline components, as well as their orientation factors, could be determined. Concerning the undrawn, conditioned yarns, it was found that the amount of γ type increases with the winding speed. The γ crystals are much better oriented than the α crystals, and the crystal dimensions of the γ structure largely depend on the winding speed in contrast to those of the α crystals. Indications were found that γ crystals are mainly generated from orientation-induced nuclei at speeds higher than 2500 mpm and that α crystals grow slowly at relatively low temperatures after moisture pickup during conditioning. Drawing at high ratios causes a transition from γ to α, while the thermal stability of the γ crystals appears to be slightly below that of the α crystals, resulting in γ crystal to α crystal transitions at extremely high temperatures or under usual autoclaving conditions.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1981.070260229
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  • 6
    Electronic Resource
    Electronic Resource
    Infrared spectra of poly(ethylene terephthalate) yarns. Fitting of spectra, evaluation of parameters, and applications (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 3069-3093 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A quantitative model for fitting infrared spectra of polyethyleneterephthalate samples over the region from 1100 to 720 cm-1 has been evaluated. The absorbance was described as the sum of a linear base line and a set of symmetrical bell-shaped Pearson VII curves. Using this model, experimental transmission spectra of yarns, measured with the electric vector parallel and perpendicular to the fiber axis, were fitted. It was found that each of the trans bands near 972 and 845 cm-1 consists of two components, a narrow and a broad one. These two components represent the crystalline and amorphous phases respectively. The band due to the out of plane benzene ring C—H deformation vibration at about 875 cm-1 appeared also to be composed of two contributions. In this case, the narrow component was found to be due to molecules having interactions with direct neighbors. So this narrow component not only contains the molecules in the crystalline phase but also those forming part of bundles which are too small to be detected by x-ray diffraction. For a detailed insight into the molecular arrangement of the amorphous regions, the infrared detection of trans-guache transitions, fold content, detection of bundlelike structures, and molecular stress on tie molecules turned out to be of great practical importance. The structural details, which can be revealed by the infrared technique, cannot be obtained by other means. The potential of the method is illustrated with some practical examples.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1985.070300728
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  • 7
    Electronic Resource
    Electronic Resource
    A quantitative description of the effect of process conditions on the physical structure of poly(ethylene terephthalate) yarns with an application to dyeing behavior (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 943-965 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The intrinsic properties of a yarn are brought about by its physical structure. This structure in its turn is controlled by the process conditions applied. A quantitative description is given of the effect of temperature, time, and tension during annealing on the structure of poly(ethylene terephthalate) yarns. Annealing of a yarn at elevated temperature leads to improvement of packing of the molecules within the crystals. Consequently, the crystalline density is not a constant but is largely dependent on the conditions under which crystallization has taken place. The growth of the PET crystals is not an isotropic process; the strongest growth is observed in the direction of the dipole interactions. The effects of tension and annealing time are also discussed. A prolonged annealing time causes an increase in crystallinity, while time and tension influence the growth of the crystals to some extent. However, for the experimental conditions used in this investigation, temperature is by far the most important factor. Generally speaking, PET fibers annealed at low temperature show low crystallinity built up of many small crystals. Yarn annealed at a high temperature, on the other hand, is composed of fewer big crystals together with large adjacent amorphous regions and relatively high overall crystallinity. Finally, the effect of this observed structural morphology on the dyeing behavior of PET yarns is discussed in a qualitative way. Two main effects controlling the dye uptake of PET yarn are proposed, viz., the total amount of amorphous regions and the accessibility of these regions.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1978.070220407
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of winding speed on the physical structure of as-spun poly(ethylene terephthalate) fibers, including orientation-induced crystallization (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 2229-2243 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: As-spun fibers of poly(ethylene terephthalate), PET, made at winding speeds ranging from 2000 to 6000 m/min exhibit quite different physical structures. Yarns wound at relatively low speeds are amorphous, whereas those spun at high speeds contain well-developed crystals of closely packed molecules. In this study the structures have been characterized by means of various techniques such as differential scanning calorimetry, x-ray diffraction, density, and pulse propagation measurements. Based on the results obtained, an arrangement of the molecules in the various yarns is proposed. It is shown that these arrangements can account for the extreme wide variety in contraction behavior found experimentally. Finally, the results obtained are compared with those of other investigations into orientation-induced crystallization.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1978.070220815
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  • 9
    Electronic Resource
    Electronic Resource
    Quantitative information from x-ray diffraction of nylon-6 yarns. II. Physical aspects of some quantitative parameters (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 941-954 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A mathematical model developed in an earlier paper describes the experimental x-ray profiles of equatorial nylon-6 reflections in terms of Pearson VII functions. The present paper deals with the physical aspects and interpretations of the interrelations of the parameters obtained and the relation between these parameters and the results of other types of measurements. It was found that the growth of the crystallites perpendicular to the chain axis is not isotropic, the strongest growth being in the direction of the hydrogen bonds. Growth and perfection of the crystallites are found to be highly correlated. Large crystals are related to short distances between the planes containing the hydrogen bonds and so to densely packed, i.e., perfect unit cells. This correlation forms the basis for the observed similarity between our quantification technique and the method of the crystal perfection index introduced by Statton. Curve resolution, however, makes the method better applicable for poorly crystallized samples. Comparison of the results with those of small-angle x-ray scattering gave a high degree of consistency with respect to the determined crystal size. In the literature mention is made of a relation between the dimensions and the melting point of the crystals; this relation is confirmed by comparing the appropriate x-ray parameters with DTA results of methoxymethylated nylon 6-yarns.Information about the γ-phase can be obtained from equatorial and meridional reflections. The expected relationship between the relevant peak areas was established. This reported evidence shows the physical validity of the parameters obtained using the Pearson VII model for the analytical description of x-ray reflections of nylon-6 yarns.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.180140515
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  • 10
    Electronic Resource
    Electronic Resource
    Quantitative information from x-ray diffraction of nylon-6 yarns. I. Development of a model for the analytical description of equatorial x-ray profiles (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 921-940 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A wide-angle x-ray method has been developed by which quantitative structural information can be obtained on nylon-6 yarns. To this end, experimental equatorial diffractometer scans measured in transmission were fitted to a mathematical model describing the profiles as the envelopes of three bell-shaped functions. Four different models were investigated using, respectively, Gauss, Lorentz (Cauchy), Logistic, and Pearson-VII functions. The last model, which can be regarded as a generalized Lorentz function, gave the best fit. On the basis of a statistical analysis of the results of well-separated x-ray peaks, two parameters could be fixed. Another reduction of the number of parameters was achieved by interrelating the peak areas of the two outer reflections. These reductions widened the applicability of a computer program based on the aforementioned model to highly overlapping x-ray peaks. So the whole variety of x-ray scans, which can be obtained from nylon-6 yarns made under widely varying process conditions, can be well described. The fitting procedures provide unique solutions and hence objectively determined parameters.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.180140514
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