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  • 1
    Electronic Resource
    Electronic Resource
    High-strain tensile deformation of a sphere-forming triblock copolymer/mineral oil blend (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 1625-1636 
    Details
    ISSN: 0887-6266
    Keywords: mechanical behavior ; block copolymers ; affine strain ; SAXS ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Films of a blend of styrene-isoprene triblock copolymer and mineral oil have been simple-cast and roll-cast from a toluene solution. Their microstructure has been analyzed by transmission electron microscopy and small-angle X-ray scattering. The blend formed polystyrene spheres arranged on a body-centered cubic lattice in a matrix composed of polyisoprene and mineral oil, and the samples display large grain sizes and very long-range order. The roll-cast sample exhibits approximately uniaxial symmetry around the rolling direction, which corresponds to the [111] crystallographic direction of the lattice. The glassy spheres act as physical crosslinks of known crosslinking functionality in the soft rubbery matrix. The high-strain deformation mechanism of this oriented cubic material has been studied by a simultaneous tensile-SAXS experiment, where the sample was stretched up to 300% along the [111] direction. By monitoring the position of the (222) and (110) reflections, the deformation of the lattice is shown to be affine with the macroscopic deformation of the sample, and the Poisson's ratio is approximately 0.46. The first zero of the sphere form factor in the SAXS patterns remains also essentially unchanged up to 300% deformation indicating that the reinforcing glassy PS domains retain their spherical shape throughout the deformation. Deformation of the microstructure is totally reversible upon unloading. A model of {hk0} faults is proposed to describe the microstructural changes induced by high-strain deformation. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1625-1636, 1998
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Roll-Casting of block copolymers and of block copolymer-homopolymer blends (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 32 (1994), S. 341-350 
    Details
    ISSN: 0887-6266
    Keywords: block copolymers ; microphase separation ; roll-casting ; single-crystal texture ; blends ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An improved technique for casting highly oriented films of block copolymers from solutions subjected to flow is presented. Polymer solutions were rolled between two counter-rotating adjacent cylinders while at the same time the solvent was allowed to evaporate. As the solvent evaporated, the block copolymers microphase separated into globally oriented structures. Using this method known as ‘roll-casting’ we present in this paper a study of the morphology of polystyrene-polybutadiene-polystyrene (PS/PB/PS) triblock copolymer cast with and without additional high molecular weight homopolymers. The pure copolymer films consisted of polystyrene cylinders assembled on a hexagonal lattice in a polybutadiene matrix in a near single-crystal structure. Blends of copolymer with high molecular weight polystyrene and/or polybutadiene, phase separated into ellipsoidal regions of homopolymer embedded in an oriented block copolymer matrix. Annealing the films resulted in conversion of the homopolymer regions to spheres accompanied by some misalignment of the copolymer microdomains. The morphology of these films as revealed by TEM is discussed. A brief discussion of the flow field that develops in the experimental system is also presented and its similarity to the flow field of our previous work is shown. © 1994 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1994.090320216
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  • 3
    Electronic Resource
    Electronic Resource
    Microphase separation of block copolymer solutions in a flow field (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 37-46 
    Details
    ISSN: 0887-6266
    Keywords: block copolymers ; microphase separation ; roll-casting ; single-crystal texture ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Films of polystyrene-polybutadiene-polystyrene (PS/PB/PS) triblock copolymer and polystyrene-poly(ethylene/propylene) (PS/PEP) diblock copolymer were cast from toluene solutions subjected to hydrodynamic flow at room temperature using a device based on a novel casting method we term ‘roll-casting.’ Polymer solutions were rolled between two corotating eccentric cylinders while at the same time the solvent was removed at a controlled rate. As the solvent evaporated, the block copolymers microphase separated into globally oriented structures. A discussion of the flow field that develops during roll-casting is presented and specific attention is given to the importance of the shear and elongation rates present. For the triblock and diblock, respectively, the processed structures consisted of polystyrene cylinders assembled on a hexagonal lattice in a polybutadiene matrix, and unidirectional lamellae of alternating polystyrene and polyethylene/propylene. Small-angle x-ray scattering (SAXS) and transmission electron microscopy (TEM) indicated the near single-crystal structure both types of films. SAXS also showed the styrene cylinders and the alternating lamellae to be packed closer together in roll-cast films than in simple quiescently cast films. A molecular orientation mechanism is proposed to describe both these results as well as the changes in packing and in macroscopic sample dimensions measured after complete solvent evaporation and after sample annealing. © 1993 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1993.090310106
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  • 4
    Electronic Resource
    Electronic Resource
    The structure of MDI/BDO-based polyurethanes: Diffraction studies on model compounds and oriented thin films (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1915-1932 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyurethanes based on MDI/BDO are known to crystallize in three distinct forms. Two of these crystal structures, type II and type III, have been characterized by electron and x-ray diffraction experiments on model compounds and oriented thin films of a 77% hard-segment polyurethane elastomer. The model compounds were of the form BDO(MDI/BDO)n with n = 1, 2, 3. Results from the model compounds indicate that the MDI/BDO repeat crystallizes in the type-II structure, which has a contracted conformation with a monomer repeat length of 1.70 nm. MDI/BDO-based polyurethanes also exhibit the type-II structure under quiescent crystallization conditions. Studies of oriented thin films of an MDI/BDO-based polyurethane indicate that a change in crystal form occurs on stretching to the fully extended monomer conformation. This crystal form is termed type III and has a monomer repeat length of 1.92 nm.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230913
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Deformation morphology of polyester single crystals (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 799-809 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Truncated, six-sided single crystals of a 10-16 linear polyester were grown from dilute solution in hexanol, deposited onto Mylar film, and uniaxially deformed at room temperature. For elongations below 10%, the crystals deform uniformly; however, above 20% elongation many cracks spanned by fibrils of 300 Å diameter develop approximately normal to the applied stress direction. Depending on the position of the crystal relative to the draw direction, lateral buckling pleats and cleavage cracks can also occur. Collapse of the nonplanar crystals onto the substrate with a resulting nonuniform adherence of the crystal influences the deformation. The deformation morphology is compared to that of truncated sixfold sector polyethylene crystals. Most notably, in contrast to polyethylene, {010} fold sectors do not deform differently from {110} fold sectors and phase boundaries between {110} and {010} fold sectors do not fracture easily.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.180140503
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