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  • 1
    Electronic Resource
    Electronic Resource
    Electro-optic scattering studies on deoxyribonucleic acid (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 1361-1372 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Measurements have been made of the intensity of light scattered from aqueous solutions of calf thymus DNA with and without the application of electric fields. For fields approaching 150 V/cm and frequencies below 2.5 KHz, changes (ΔI) of up to 10% in the residual scattered intensity were observed. In agreement with previous dielectric and electric birefringence measurements, a low frequency dispersion of ΔI was observed, from which a rotary diffusion constant (D) of 1200 s-1 was determined. Interpreting the electric field data in terms of the classical dipolar orientation theory led to values of 2.4 × 10-25 cm (7.4 × 10-14 esu) and 4.3 × 10-25 cm (13 × 10-14 esu) for the permanent dipole moment and the anisotropy of the electric polarisabilities respectively. Furthermore the permanent dipole moment was along the major molecular axis and the particles orientated in the field as rigid entities. The zero field data indicated a molecular shape which was not rodlike but corresponded to the Kratky-Porod “stiffness” parameter of x = 24 for the wormlike coil model. Although curved, the molecules appeared to orientate in low-intensity electric fields as rigid, but not rodlike molecules. The implications of this on recent discrepancies in D determined by two or more dynamic relaxation methods is briefly discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360091106
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  • 2
    Electronic Resource
    Electronic Resource
    Phase morphology of as-molded and annealed blends of polyarylate/copolyester (1989)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 29 (1989), S. 1493-1502 
    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 phase morphology of injection molded blends of polyarylate (PAR) and a copolyester (PCTG-5445) was studied by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The use of ultramicrotomy to prepare ⋍ 50 nm thin section TEM specimens and solvent etching to dissolve the PAR phase revealed PCTG as the matrix phase in the as-molded state which crystallized into PCTG spherulites upon annealing. The most consistent morphological information vs. concentration of PCTG and the highest structural integrity of the PCTG spherulites was obtained from thin sections treated with a mixture of 75% methylene chloride as the solvent for the PAR and 25% 2-propanol as the nonreactive diluent. XRD results from the annealed PCTG/PAR blends show crystalline reflections of 0.59, 0.53, 0.46, 0.38, and 0.35 nm, which disappear into the amorphous background below 50% PCTG.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760292102
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  • 3
    Electronic Resource
    Electronic Resource
    Confined-growth crystallization of polyethylene (1972)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 507-517 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new typical orientation pattern of polyethylene has been observed in extruded, melt-drawn composites containing 10% polyethylene and 90% polystyrene. In these composites, the polyethylene phase is dispersed in the polystyrene matrix as thin, long ribbons (width 1000 Å, thickness 500 Å). The b axis of the crystallites is found oriented preferentially along the long dimension of the ribbons, i.e., in the extrusion direction. The a and c axes of the crystallites show no preferred orientation. This texture pattern is attributed to the fact that, in view of the small cross section of the polyethylene phase, crystallization can proceed only along the long axis of the ribbons. Since the b axis is the direction of fastest growth in polyethylene (and the radial direction in a spherulite), most polyethylene unit cells are oriented with their b axes in the long dimension of the ribbons.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1972.160100307
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  • 4
    Electronic Resource
    Electronic Resource
    Mean field calculations of the dynamic mechanical properties of two-phase elastomer blends: Included particles in a matrix phase (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 37 (1989), S. 1877-1888 
    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: Mean field theories developed by Kerner and van der Poel were applied to several binary elastomer blends. Calculations were compared with experimental small strain dynamic mechanical properties of the blends. Although the blends exhibit a wide range of detailed structures, the theories were able to model blenas with well-defined included particles embedded in a matrix phase. Blends with a continuous morphology were not properly modeled with the Kerner or van der Poel theories.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1989.070370711
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  • 5
    Electronic Resource
    Electronic Resource
    Characterization of polymer composites by electron microprobe analysis (1972)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 12 (1972), S. 34-40 
    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: This paper describes the use of an electron microprobe for characterizing filler and polymer dispersios in polymer composites. Examples described are: filler distribution in sisal reinforced polyester; aggregation of titanium dioxide in glassreinforced polyester; mixing behavior in a blend of silicone rubber, natural rubber, and titanium dioxide; and distribution of silica in a low-gloss paint on an ABS plastic surface. The limitations of electron microprobe analyses for qualitative and quantitative studies, the use of back scattered electrons for surface topography, and techniques for preparing specimens are mentioned.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760120106
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  • 6
    Electronic Resource
    Electronic Resource
    Transmission electron microscopy of ultramicrotomed barrier anodic films on aluminium (1982)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 4 (1982), S. 257-260 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Ultramicrotomy was utilized to produce thin section specimens of anodized aluminium to permit a measurement of the film thickness in cross section by transmission electron microscopy. This direct approach to film thickness measurement has an inherent precision of ±0.5 nm, and may be utilized to measure films as thin as 5.0 nm. Two types of film growth procedures were studied using this technique: one utilizing an aqueous ammonium tartrate solution as the electrolyte, and a second using a nonaqueous electrolyte of ammonium pentaborate in ethylene glycol. While both electrolytes yielded barrier values of approximately 1.5 nm V-1, in agreement with literature values, the aqueous electrolyte tended to show a zero-potential offset of nearly 10 nm greater than the nonaqueous electrolyte. Furthermore, films grown in aqueous solutions tended to have a less dense surface morphology, which was distinguishable in transmission electron microscopy.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740040608
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