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  • Wiley-Blackwell  (16)
  • Oxford University Press  (1)
  • American Institute of Physics (AIP)
  • American Chemical Society (ACS)
  • 1980-1984  (17)
  • 1955-1959
  • 1983  (17)
  • 1
    Electronic Resource
    Electronic Resource
    Three-dimensional organization of the platelet cytoskeleton during adhesion in vitro: Observations on human and nonhuman primate cells (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 589-608 
    Details
    ISSN: 0886-1544
    Keywords: platelet ; platelet adhesion ; cytoskeleton ; high voltage electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Adhesion of platelets in vitro resulted in rapid polymerization of the amorphous cytoplasmic ground substance into an organized cytoskeletal superstructure. This cytoskeleton, characterized through the use of whole-mount and stereo (3-D), high-voltage microscopy in conjunction with morphometrics and cytochemistry, comprised four major size classes of filaments organized in distinctive zones. The central matrix, or granulomere, at the center of the cell mass, was an ill-defined meshwork of 80-100-Å filaments which enshrouded granules, dense bodies, and elements of the dense tubular system as identified through peroxidase cytochemistry. Demarcasting this central matrix was a trabecular zone containing 30-50, 80-100, and 150-170 Å filaments in an open and rigid-appearing lattice. Circumscribing the trabecular zone and extending to the margins of the hyalomere was the third region, the peripheral web, in which 70-Å filaments were arranged in a tight honeycomb lattice. This organizational pattern was retained in cytoskeletons prepared by Triton x-100 extraction of the adherent cells, and was observed in basally located cells of aggregates which formed subsequent to adhesion. Our observations are consistent with biochemical studies of cytoskeletons prepared from suspended platelets and suggest a contractile protein composition for the superstructure during adhesion.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970030525
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  • 2
    Electronic Resource
    Electronic Resource
    On the minimum draw ratio necessary for full chain extension: Illustrated with polyethylene (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 21 (1983), S. 1005-1010 
    Details
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.130211207
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  • 3
    Electronic Resource
    Electronic Resource
    The surface orientation of polystyrene measured by liquid contact angle (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 28 (1983), S. 1439-1445 
    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 surface contact angle of glycerol and of water on polystyrene (PS) films has been found to depend on the extent of uniaxial draw for atactic PS. The contact angle depends on direction for the smooth films of PS drawn by solid state coextrusion. Results as a function of draw ratio to values over 4 on these noncrystalline PS samples, Mw = 6 × 105, have also been interrelated with other measures of orientation such as the anisotropy of surface and bulk properties measured, respectively, by dichroic reflectance infrared spectroscopy and by birefringence.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1983.070280417
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  • 4
    Electronic Resource
    Electronic Resource
    Photooxidation of polystyrene: Irradiation at 254 and 365 nm (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 28 (1983), S. 3227-3233 
    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: Studies have been made of the near surface photooxidation of atactic polystyrene films prepared in the absence of air. The samples were photooxidized on exposure to air at two frequencies, 254 and 365 nm, using a calibrated mercury irradiation source with filters. Most studies were made at 40°C and as a function of irradition time with the reactions characterized by changes in molecular weight and composition. The former was evaluated by gel permeation chromatography and the latter by transmission Fourier transform infrared spectroscopy and by multiple-internal-reflectance infrared spectra using different angles and different crystals to evaluate compositions as a function of film depth. Species identified in photooxidation include the generation of hydroperoxides and the appearance of carbonyl bands with the latter identified by the spectral shift asociated with the exposure of the photooxidized polystyrene surface to ammonia. These results suggest that principal products of near-surface oxidation of polystyrene are carboxylic acids.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1983.070281017
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  • 5
    Electronic Resource
    Electronic Resource
    Fourier-transform infrared study of coextrusion-drawn poly(ethylene terephthalate) (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 389-400 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effects of initial morphology and extrusion temperature on the orientational anisotropy and conformational changes on coextrusion drawing of poly(ethylene terephthalate) (PET) have been determined by Fourier-transform polarized infrared spectroscopy. The samples were drawn from both amorphous and semicrystalline (50%) PET at 50 and 90°C. A strong influence of coextrusion drawing temperature was observed for overall chain orientation evaluated from the dichroic ratio of the 795-cm-1 band for the samples prepared from the amorphous state: this dependence was less prominent in samples drawn from the semicrystalline state. Under the same drawing conditions, the dichroic ratio for the 973-cm-1 trans band for samples prepared from the amorphous state was higher than from the semicrystalline state. Furthermore, in all samples, the relative intensity of this band was almost proportional to the degree of crystallinity. In all samples, the gauche content, evaluated from the 896-cm-1 band, decreased with increasing draw ratio. However, the dichroic ratio of this band was near unity regardless of draw ratio, initial morphology, or extrusion temperature. From these results it is considered that all gauche units in the amorphous phase are almost isotropic in the extrusion-drawn samples with overall orientation arising largely from the crystalline chains possessing totally the trans conformation (973 cm-1) in its content. In order to evaluate the deformation mechanism of the coextrusion drawing method, the relationship between the bulk and film surface orientation is also reported.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.180210306
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  • 6
    Electronic Resource
    Electronic Resource
    Solid-state coextrusion of poly(ethylene terephthalate). I. Drawing of amorphous PET (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 1133-1145 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Films of uniaxially oriented poly(ethylene terephthalate) (PET), Mv = 81,000, have been drawn by solid-state coextrusion in the range 40-100°C surrounded by polyethylene. This is well below the PET melting temperature and in some cases below its glass transition temperature. Properties of the extrudates, such as degree of crystallinity, mechanical and thermal properties, were investigated as a function of coextrusion temperature and draw ratio (EDR ≤ 4.4). The results show that the percent crystallinity depends strongly on draw ratio, whereas its sensitivity to extrusion temperature is limited only to the highest draw ratio (4.4). On the other hand, Young's modulus was sensitive to both extrusion temperature and draw ratio, exhibiting a maximum at EDR = 4.4 and Text = 65°C. Above this temperature, moduli decrease apparently because of increased chain mobility, resulting in dissipation of chain orientation. Furthermore, changes in yield and tensile strength followed the changes in mechanical properties, suggesting that they are dominated by the same factors. The cold-crystallization temperature TCC also revealed information about the morphological changes occurring during the extrusion drawing. For samples of EDR = 4.4, TCC increased with extrusion temperature, suggesting again dissipation of orientation by thermal motions. On the other hand, TCC decreases with EDR, and a ΔTCC as high as 73°C was found. Conventional drawing of amorphous PET has been widely reported. To our knowledge this is the first time oriented PET has been prepared using the advantages of solid-state coextrusion.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.180210713
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  • 7
    Electronic Resource
    Electronic Resource
    Solid-state coextrusion of poly(ethylene terephthalate). II. Drawing of semicrystalline PET (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 1147-1161 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The drawing of semicrystalline (33 and 50%) poly(ethylene terephthalate) (PET) films has been studied by solid-state coextrusion. Because of its brittleness and opacity, isotropic and semicrystalline PET film is of little practical use. Early attempts to cold-draw crystalline films led to fracture in contrast to deformation of amorphous PET. However, we have succeeded in systematically preparing films with extrusion draw ratios ≤4.4 from semicrystalline PET. In many cases, the properties of the drawn extrudates, as a function of extrusion temperature Text and extrusion draw ratio EDR, were similar to those prepared from amorphous PET. However, some remarkable differences have also been found. In the case of coextrudates prepared from isotropic 50% crystalline PET, we found that the larger the deformation, the lower the apparent resulting crystallinity. In the extreme, a 34% reduction in crystallinity after deformation was observed. For the coextrudates drawn from initially 33% crystalline PET, slightly different behavior occurred. For Text ≤ 90°C, all extrudates showed crystallinities lower than the original isotropic film, with a minimum at EDR = 3; for Text ≥ 110°C, crystallinities were slightly greater than in the original film and increased with EDR. Qualitative measurements of heats of fusion were in agreement with density gradient results for PET crystallinity. In contrast is our previous finding that extrudates from initially amorphous PET always increase in crystallinity with EDR, because of stress-induced crystallization. The results now suggest that in the Text range investigated, the initial spherulitic structure is at least in part destroyed on drawing. In addition, the percent crystallinity is revealed to be dependent on Text, with lower values at lower temperatures. Mechanical tests show that the extrudates are similar or sometimes higher in tensile modulus when compared to amorphous PET drawn under the same conditions.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.180210714
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  • 8
    Electronic Resource
    Electronic Resource
    Chain orientation in polystyrene/poly(2,6-dimethyl-1,4-phenylene oxide) blends (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 1815-1823 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The differential orientation of polymer chains has been measured in polystyrene (PS)/poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) compatible blends. Density measurements are reported as a function of binary blend composition at 23°C. Drawing was performed by solid-state coextrusion. PS/PPO blend compositions of 90/10 and 75/25 were drawn within sandwiches of polyethylene at 145°C and isotactic polypropylene at 155°C, i.e. at ca. 25°C above the glass transition temperatures of the two blends. The change in Fourier-transform infrared dichroisms on drawing these blends was measured at 906 and 1190 cm-1, corresponding to predominantly PS and PPO, respectively. The orientation of PS and PPO was observed as a function of draw ratio λ in the range 1-5; orientations increased with λ for both PS and PPO in both blends but to different degrees. Both polymers decreased in orientation with increasing PPO content. Annealing with fixed ends showed that the PPO chains disorient more slowly than those of PS. All binary systems were found to be amorphous and compatible.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.180210917
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  • 9
    Electronic Resource
    Electronic Resource
    Thermal expansivity of oriented poly(ethylene terephthalate) (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 1427-1438 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The linear thermal expansivity of poly(ethylene terephthalate) extruded at 50 and 90°C to extrusion ratios λ of 1-4.8 has been measured between 120 and 300 K. With increasing λ, the expansivity along the extrusion direction (α∥) decreases sharply, while that in the transverse direction (α⊥) shows a slight increase. For λ 〈 3, the large drop in α∥ and the accompanying increase in the axial Young's modulus E∥ can be ascribed to chain alignment in the crystalline regions and to an increase in number and tautness of intercrystalline tie chains. At higher λ, however, the crystalline orientation apparently becomes saturated, so that taut tie molecules are solely responsible for further changes in both α∥ and E∥. On the other hand, α⊥ is mainly determined by crystalline orientation for all λ, thus showing very little increase at large λ. For the highly oriented samples (λ ≥ 3), the Takayanagi model provides a reasonable description of the behavior of α∥ and α⊥.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.180210813
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  • 10
    Electronic Resource
    Electronic Resource
    Annealing of ultra-oriented high density polyethylene extrudates (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 521-529 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 annealing characteristics of highly-oriented, high density polyethylene (HDPE) fibers extruded at 90°C to constant extrusion draw ratios (EDR) of 5.8 to 30 have been studied using small-(SAXS) and wide-angle (WAXD) x-ray diffraction, differential scanning calorimetry (DSC), thermal shrinkage and tensile tests. The thermal stability in macroscopic properties, such as transparency, sample dimension, and tensile modulus, remarkably increases with the sample EDR. However, the folded chain crystals within microfibrils sensitively reorganize on annealing at ≥ 110°C, even when the macroscopic properties exhibit no significant changes at high EDR's. Although the EDR has a minor effect on the reorganizability of the fold chain crystals, it has a major influence on the SAXS intensity and the extended chain crystalline component detected by WAXD for both unannealed and annealed extrudates. This specific crystalline component has an improved thermal stability and enhances the thermal stability of macroscopic properties at higher EDR. The fibers extruded at 90°C in this study and those prepared at 134°C in a prior study, exhibit significantly different melting behavior after annealing and for long period vs. EDR relationships. These facts combined with the independent observations of the effect of annealing and extrusion temperatures on the consequent long period strongly suggest that annealing during extrusion plays an important role in determining the microstructure of extrudates, especially for extrusion near the ambient melting point of the polymer.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760230908
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