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  • 1
    Electronic Resource
    Electronic Resource
    Dynamic small-angle scattering system for the study of materials deformation and relaxation (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 26 (1988), S. 745-770 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A dynamic small-angle x-ray scattering system (DSAXS) for the study of materials deformation and relaxation has been developed in the National Center for Small-Angle Scattering Research, Oak Ridge National Laboratory (NCSASR-ORNL), in collaboration with Polymer Research Institute of the University of Massachusetts. The principles of DSAXS are outlined, including experimental procedures such as π-sector and Fourier expansion techniques. A few important functions required for studies of crystalline polymers, namely, static and dynamic lamellar orientation, dynamic lamellar separation, dynamic invariant function, etc., are defined. The hardware and software of the DSAXS system are described. Some preliminary results obtained for a spherulitic high-density polyethylene by π-sector technique and for a row-nucleated polybutene-1 by Fourier expansion techniques are demonstrated to evaluate the performance of the system.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1988.090260403
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  • 2
    Electronic Resource
    Electronic Resource
    Cocrystallization and miscibility studies of blends of ultrahigh molecular weight polyethylene with conventional polyethylenes (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 32 (1986), S. 5575-5584 
    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: Ultrahigh molecular weight polyethylene (UHMWPE) was mechanically mixed with conventional polyethylenes (LLDPE, HDPE, and LLDPE) using an internal mixer. Rheological studies of these blends suggest that UHMWPE seems to be miscible with LLDPE, HDPE, and LDPE in the melt state. Yield characteristics are observed in all blend systems, particularly in high UHMWPE blend compositions. Differential scanning calorimetry and small-angle light scattering studies show that cocrystallization takes place in the blends of UHMWPE/LLDPE and UHMWPE/HDPE blends. However, separate crystals are formed in UHMWPE/LDPE. The formation of separate crystals may be attributed to long chain branching of conventional low-density polyethylene. Tensile properties of the former two blends vary almost linearly with blend compositions, while deviations are seen in the latter UHMWPE/LDPE blends.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1986.070320625
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  • 3
    Electronic Resource
    Electronic Resource
    Single-Phase blends of polycarbonate and poly(phenyl methacrylate) (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 44 (1992), S. 2233-2237 
    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: Miscibility studies on blends of polycarbonate (PC) and poly(phenyl methacrylate) (PPMA) were undertaken by means of differential scanning calorimetry (DSC), dynamic mechanical, and dielectric relaxation methods. PC and PPMA were mixed by dissolving in tetrahydrofuran (THE) and subsequently coprecipitated in methanol. DSC studies showed a single glass transition (Tg) that shifts systematically with composition. These Tgs are reproducible in repeated DSC heating cycles, suggesting true miscibility of the pair. The dry PC and PPMA pellets were melt mixed in a Mini-Mixer/Molder. The extrudates were compression molded. These melt-mixed PC/PPMA blends exhibited glass like transparency and also showed a single Tg in the DSC scans. The true miscibility of PC and PPMA was further confirmed by dynamic mechnaical and dielectric relaxation methods. The net birefringence has been reduced substantially because of the opposite sign of the itrinsic birefringence of PC and PPMA molecules. At the 12/88 PC/PPMA, the birefringence remains zero at all draw ratios, indicating the achievement of birefringence free polymer alloys.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070441220
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  • 4
    Electronic Resource
    Electronic Resource
    Miscibility in poly-p-phenylene terephthalamide/nylon 6 and nylon 66 molecular composites (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 37 (1989), S. 201-213 
    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: Miscibility and crystallization of poly-p-phenylene terephthalamide (PPTA)/nylon 6 and nylon 66 composites prepared by coagulation of isotropic ternary sulfuric acid solutions were studied. The apparent crystallinity of nylon 6 and nylon 66 in molecular composites was investigated by differential scanning calorimetry and Fourier transform infrared spectroscopy. The solvation of nylon 6 crystals in PPTA matrix was observed when the PPTA content exceeds 70 wt%. Cross-hydrogen bonding seems to be responsible for the virtual disappearance of nylon 6 crystals. Specific interaction between PPTA and nylon 6 macromolecules and phase separation during thermal treatment has been discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1989.070370115
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  • 5
    Electronic Resource
    Electronic Resource
    Dynamic x-ray diffraction studies of high-density polyethylene (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 329-352 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Dynamic x-ray diffraction is conducted to explore the structural origin of the α and β mechanical dispersions of a melt-crystallized high-density polyethylene. It is shown that the real component of the strain orientation coefficient for the crystal c axis C′c decreases with increasing frequency at a rate which decreases with decreasing temperature. Values of C′c for the c axis are positive, C′a for the a axis negative, and C′b for the b axis close to zero, suggesting that the predominant relaxation process is crystal rotation about the b axis. The activation energy found from Arrhenius plots of C*k corresponds to that of the α1 mechanical dispersion. The dynamic birefringence in this region is dominated by the contribution from crystal orientation changes. At low temperatures, the imaginary component KC″cr of the strain-optical coefficient of the crystal phase approaches zero, while KC″am of the amorphous phase exhibits a somewhat broad dispersion peak corresponding to the β birefringence dispersion. This suggests that the principal contribution to the β birefringence dispersion arises from the amorphous phase, probably owing to the amorphous orientation process. Contrary to the case of low-density polyethylene, the dynamic crystal lattice deformation and compliance functions reveal distinct frequency dispersions corresponding to the α1 and α2 mechanical processes. The α1 lattice dispersion is thought to be associated with the α1 crystal orientation dispersion, while the α2 lattice dispersion is believed to be the inherent one arising from the onset of intracrystalline chain motions.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.180210302
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  • 6
    Electronic Resource
    Electronic Resource
    Dynamic small-angle x-ray scattering from crystalline polymers (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 881-892 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The variation in small-angle x-ray scattering (SAXS) for samples of crystalline polymers subjected to oscillatory strains has been observed employing the 10-m SAXS apparatus with a two-dimensional position-sensitive detector at the National Center for Small-Angle Scattering Research at Oak Ridge National Laboratory. Signal averaging has been carried out in accordance with the π/2-sector technique by gating the detection of scattered intensity in synchronism with the sample strain. In-phase and out-of-phase intensity changes have been observed for a high-density polyethylene at various frequencies (0.05-3.2 Hz) and temperatures (0-70°C). Changes are greatest at small scattering angles. Frequency dependence is greatest at lower temperatures, indicating a time-dependent response of the structural changes leading to scattering at these temperatures. The behavior is not pronounced at elevated temperatures. The similarity of the scattering at both azimuthal angles of 0° and 90° suggests the existence of an additional mechanism, perhaps microvoid formation. To evaluate void contribution, the dynamic invariant function is determined as a function of frequency and temperature. It appears that the microvoid formation lags behind the applied strain. The static and swelling SAXS studies present further evidence of void generation during elongation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.180210605
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  • 7
    Electronic Resource
    Electronic Resource
    Rheo-optical studies on the deformation mechanism of semicrystalline polymers. IV. On the nature of alpha mechanical dispersion of low density polyethylene in relation to the mechanism of spherulite deformationPresented at the 7th International Congress on Rheology, Gothenburg, Sweden, August 27, 1976.Previous papers in this series appeared in Polymer J., 7, 108 (1975); 8, 565 (1976); 10, 315 (1978). (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 17 (1979), S. 763-790 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dynamic mechanical and birefringence behavior of three kinds of test specimens, prepared from a low-density polyethylene by different heat treatments, was investigated over the frequency range 0.008 to 4.3 Hz at various temperatures from 20 to 80°C. Reduction of both kinds of data to the common reference temperature of 50°C revealed rather broad frequency dispersions, corresponding to the α dispersion, with activation energies for the mechanical and optical relaxation processes of around 25 kcal/mole for all specimens. An annealed specimen was further investigated by dynamic x-ray diffraction to determine the dispersions of crystal orientation and of lattice deformation. The mechanical and birefringence dispersions are associated with the dispersion of crystal orientation and with the relatively elastic nature of the lattice deformation. Thus, the mechanical dispersion could be assigned to an α1 mechanism arising from rotation of crystallites within the spherulites, i.e., a type of grain-boundary phenomena, but not to an α2 mechanism resulting from a crystal disordering transition or premelting. Combining dynamic birefringence with dynamic crystal orientation, the mechanical α dispersion is further discussed in terms of dynamic orientation behavior of noncrystalline chain segments in order to elucidate the nature of the grain-boundary phenomena in detail in relation to the dynamic deformation mechanism of the spherulitic crystalline texture, i.e., reorientation of “crystal grains” within orienting lamellae due to intralamellar shearing resulting from the paracrystalline nature of the lamellae. A mechanical model characterizing the grain-boundary relaxation in association with the reorientation of the crystal grain is also proposed.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.180170504
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  • 8
    Electronic Resource
    Electronic Resource
    Dynamic birefringence studies of high-density polyethylene (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 20 (1982), S. 1279-1287 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A rheo-optical investigation has been carried out on a sample of high-density polyethylene (HDPE) in an attempt to examine the nature of the α-relaxation mechanism. Dynamic mechanical and bi-refringence behavior was measured over the frequency range of 0.008-4.3 Hz and temperature range -40 to 100°C. The dynamic mechanical and birefringence data were reduced to a reference temperature of 50°C by a combination of horizontal and vertical superposition. The significance of the vertical shift factor has been discussed extensively in previous papers and is not dealt with here. An Arrhenius plot was made of the log of the horizontal shift factor versus reciprocal temperature for the mechanical and optical data. The mechanical data exhibited three distinct regions, the slopes of which led to activation energies of 70, 90, and 150 kJ mol-1. The temperature at which these dispersions occurred suggested the observation of the β, α1, and α2 relaxation processes. The optical data contained two distinct regions from which activation energies of 55 and 95 kJ mol-1 were obtained. The high-temperature α2 process was not observed in the Arrhenius plot; however, a maximum in K′ and a change in sign of K″ probably reflects a contribution from the α2 relaxation mechanism.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.180200714
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  • 9
    Electronic Resource
    Electronic Resource
    Miscible blends of polycarbonate and polymethyl methacrylate (1988)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 26 (1988), S. 33-40 
    Details
    ISSN: 0887-6258
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Solvent-cast films of polycarbonate (PC)/polymethyl methacrylate (PMMA) mixtures exhibit a single-phase structure with outstanding optical clarity. Differential scanning calorimetry (DSC) studies show a single glass transition in the intermediate blends. However, the blends undergo phase separation upon heating above 240°C. The phase diagram has been established subsequently by means of a cloud point method and is reminiscent of lower critical solution temperature (LCST) in character.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1988.140260105
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  • 10
    Electronic Resource
    Electronic Resource
    Immiscibility loop phase behavior of polycarbonate and poly(methyl methacrylate) blends (1989)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 27 (1989), S. 421-426 
    Details
    ISSN: 0887-6258
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1989.140271104
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