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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 6 (1962), S. 541-547 
    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 use of swelling anisotropy as a means of determining the orientation of cellulose fibers has been critically reviewed, and it has been shown that the method should be suitable for highly oriented fibers within a certain range of orientation. The application of the method to untreated and variously treated jute fibers reveals certain structural differences with ramie, of which the following are noteworthy. Both noncrystalline and crystalline orientations of jute are influenced by treatments which can be regarded as being confined to the intercrystalline regions only and which do not affect ramie. As compared with ramie, the ultimate maximum disorientation, produced on mercerization treatment is markedly less in jute, and this holds for both the crystalline as well as the noncrystalline components of the fiber.
    Additional Material: 5 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 6 (1962), S. 533-540 
    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: Measurements have been made of the shrinkage in alkali and of the permanent contraction resulting from alkali treatment. The results supported by x-ray evidence following the changes in orientation and degree of mercerization show that the shrinkage of jute is subject to a similar restraint as swelling, and the shrinkage behavior of jute compared to ramie is as that of a yarn compared to that of its constituent fibers. Unlike swelling, the shrinkage of jute at dilute alkali is less than that of ramie and the corresponding region of the shrinkage curve is conspicuous by the smoothness of swelling curve, indicating that the shrinkage refers primarily to the structural framework of the fiber, whereas an extrastructural material may contribute to swelling. Although the crystallinity of jute is comparable to that of rayon, no appreciable permanent contraction occurs in the fiber treated in dilute alkali, and this points to a restraint in the structure of jute similar to that exercised by the crystallites in ramie. Whereas the resistance in ramie is completely neutralized in mercerizing alkali and the whole of the alkali shrinkage remains as permanent contraction, the restraint still operates in jute, and the permanent contraction is in deficit of the alkali shrinkage. The respective disorientations are also of the same order. Both permanent contraction and crystalline disorientation continually increase on repeated alkali treatments of jute and ramie; the additional effect found in jute is its complete mercerization after a number of treatments. The shrinkage as indexed by its maximum value is strongly correlated with the oriented state of the fiber, and the disorientation produced in jute on dilute alkali treatment is followed by a lower maximum shrinkage. Incomplete disorientation of mercerized jute shows up in positive shrinkage and its proportion is the same as that of unconverted cellulose I residue. In spite of a very high degree of orientation, the reoriented fiber shows a considerably low maximum shrinkage compared to the native. This is suggested to have been due to the formation of some junction points when the freely swollen plasticized fiber is mechanically strained.
    Additional Material: 4 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 3427-3437 
    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: It was shown that the shape of the scattering pattern is not only related to the shape but also to the face-orientation of the lamellar scattering units, and an actual observation of its characteristic shape depends on the amount and dispersion of their spiral angle. The following results were obtained: (1) For observing a cross-pattern, the critical spiral angles corresponding to minimum and maximum dispersions are 7.5° and 30° respectively, whereas in an actual fiber, coir, the critical angle is about 16.75°. (2) The jute pattern changes from a uniformly narrow to a triangular shape on disorientation and reverts to the former on reorientation. The corresponding changes in ramie are from a triangular to a uniformly wide and then to a uniformly narrow shape. Both native and disoriented cottons give weak, fan-shaped scattering superimposed on a more intense elliptical pattern. The pattern given by reoriented cotton is roughly a narrow streak. Delignified jute gives a somewhat shaving-brush-shaped pattern which changes to a uniformly wide streak on alkali treatment. (3) The extent of scattering decreases on swelling and increases on stretching in jute, ramie, and cotton, but decreases in stretched coir.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 3439-3450 
    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: It was shown that the realization of a straight log I-h2 curve may be a coincidence depending on the relative influence of heterogeneity of distribution and non-independent scattering, and a concave log I-h2 curve can represent a nonhomogeneous system amenable to Shull and Roess's method of analysis. The results indicate: (1) The I-h curve for a jute holo-cellulose film has a maximum, and that for a ramie film an inflexion point, each superimposed on a background of gradually declining intensity, and in either case the singularity is accentuated and shifted to a region of larger angle on alkali-treatment. (2) The log I-h2 plots for untreated, alkali-treated and stretched jute fibers give straight sections in the low-angle, and convex, concave, and straight sections, respectively, in the high-angle region. An interesting feature of the results for ramie is the realization of a straight logarithmic curve on mercerization. The curves for alkali-treated and stretched Fortisan fibers have also each of them two discernible linear parts, indicative of two groups of scatterers. (3) An evaluation of the log I-log h2 curves by Shull and Roess's method leads to figures for the diameters of the scattering elements in ramie comparable to those estimated from the corresponding log I-h2 plots.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 25 (1980), S. 1737-1744 
    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 effect of heat treatment in the presence and absence of a nonionic surfactant (Triton X-100) on selected properties of polyester fabric was studied over the temperature range 180-220°C. Although significant heat-induced area shrinkage was evident (4.9-9.5%) in the treated polyester fabrics, stiffness, wrinkle recovery, tensile properties, moisture regain, and density of the fabrics showed only slight changes. The moisture-related properties of surfactant/heat-treated polyester were greatly improved compared to untreated control polyester or polyester subjected to heat treatment alone. Oligomer formation on the surface of surfactant-treated polyester was altered as a result of the presence of surfactant on heating compared to polyester heated alone at 180-220°C. Polyester heat treated in the presence and absence of surfactant showed increased dye uptake and more depth of color with 1,4-substituted anthraquinone dyes than untreated polyester, and these effects increased with increasing treatment temperature.
    Additional Material: 1 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 45 (1992), S. 937-945 
    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: Processing operations such as milling, change the chemical structure of rubber. Infrared (IR) spectroscopy and electron spectroscopy for chemical analysis (ESCA) have been used to detect the formation of functional groups during the milling of natural rubber (NR), epoxidised natural rubber (ENR), styrene butadiene rubber (SBR), neoprene (CR), and acrylic rubber (AR). The concentration of carbonyl () groups as detected by IR spectroscopy increases with the time of milling for all the rubbers. The concentration of hydroxyl groups (—OH) in NR and ENR also increases during milling. ESCA spectra of the rubbers before and after milling reveal that the peaks are broader for milled rubber, and that the concentration of oxygen is also greater. In the case of ENR, however, the concentration of epoxide rings decreases and that of furan rings increases with the time of milling.
    Additional Material: 12 Ill.
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  • 7
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Eine heterodisperse Probe von Polymethylmethacrylat sowie mehrere Fraktionen, die von dieser Probe erhalten wurden, wurden im Vakuum bei 300-500°C pyrolysiert. Die Proben wurden als dünne Filme auf beiden Seiten eines 260 cm langen Banddrahtes aufgebracht, der auf Grund seines Ohmschen Widerstandes erhitzt wurde (zuerst mit einem besonders starken Strom, um rasch eine hohe Temperatur zu erreichen). Die ursprüngliche Probe sowie auch der Pyrolysenrückstand wurden durch Gelpermeationschromatographie analysiert, um die Änderungen des Molekulargewichtes während der Pyrolyse zu bestimmen. Man kann auf Grund früherer kinetischer Studien erwarten, daß in dem obigen Temperaturbereich eine Änderung im Mechanismus stattfindet. Aus diesem Grunde wurde vorausgesagt, daß das Molekulargewicht einer unfraktionierten Probe während des Abbaues bei 300°C sich nicht verändert, bei 500°C aber abnimmt. Andererseits ist zu erwarten, daß das Molekulargewicht von fraktionierten Proben bei 300°C abnimmt und bei 500°C unverändert bleibt. Die Resultate stimmen mit der Vorhersage im großen und ganzen überein, aber bei 500°C verhalten sich nur die Fraktionen mit niedrigen Molekulargewichten wie erwartet. Die Arbeit bestätigt also den Mechanismus und die Voraussagen, die auf kinetische Studien begründet waren; hochmolekulare Proben bei hohen Temperaturen, bei denen eine gewisse Einschränkung bezüglich des Mechanismus notwendig ist, müssen jedoch hierbei ausgenommen werden.
    Notes: A heterodisperse sample of poly(methylmethacrylate), and several fractions derived from this sample, have been pyrolysed in vacuo at temperatures in the region of 300 and 500°C. The samples were deposited as thin films on both sides of a 260 cm ribbon filament, which was heated resistively, and also boosted to ensure a rapid initial rise in temperature. The initial samples, and the residues after pyrolysis, were analysed by Gel Permeation Chromatography to obtain the trends in molecular weight with conversion. From previous kinetic studies, a change in mechanism is expected over the above temperature range, and on this basis it was predicted that during degradation at 300°C the molecular weight of an unfractionated sample would remain invariant, but at 500°C the molecular weight of such a sample would decrease; on the other hand the molecular weight of fractionated samples is expected to decrease at 300°C and to remain invariant at 500°C. The results are in general agreement with these predictions except that at 500°C only low molecular weight fractions behave in the expected manner. This work therefore confirms the mechanisms postulated from kinetic studies, but in the case of high molecular weight samples at high temperature some qualification of the mechanism has been necessary.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 58 (1995), S. 1947-1957 
    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 blends of epoxidized natural rubber (50 mol %) (ENR) and poly(ethylene-co-acrylic acid) (PEA) (6 wt %) are demonstrated to be partially miscible up to 50% by weight of PEA and completely miscible beyond this proportion. The miscibility has been confirmed by a DSC study which exhibits a single second-order transition (Tg) for the 30 : 70 and 50 : 50 (ENR : PEA) blends. For the 70 : 30 (ENR : PEA) blend, the Tg's shift toward an intermediate value but do not merge to form a single Tg, making the blend partially miscible. The miscibility has been assigned to the esterification reaction between - OH groups formed in situ during melt blending of ENR and - COOH groups of PEA. The occurrence of such reactions have been confirmed by UV and IR spectroscopic studies. The existence of a single phase of the blends beyond 50 wt % of PEA has been shown by SEM studies. © 1995 John Wiley & Sons, Inc.
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