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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 2094-2096 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The tensile X–Y stage, providing a load cell and a stretching device, has been constructed to observe the surface deformation of polymer film in situ by using an atomic force microscope (AFM). From the three-dimensional AFM images, the streak-like bumps were observed on a polyethylene terephalate (PET) film surface. By monitoring the change in the distance between them by the tensile load, the strain was evaluated in the direction both parallel and perpendicular to the tensile direction. The microscopic stress–strain relationship by AFM coincided with the macroscopic one, which indicates so-called affine deformation of PET film. Young's modulus was obtained as 2.3 GPa for PET from the initial slope of the stress–strain curve by AFM. The apparent Poisson ratio of the PET film surface could be also evaluated. © 2000 American Institute of Physics.
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 73 (2002), S. 1809-1812 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An x-ray diffraction apparatus, consisting of a load cell, a stretching device, and a cryogenic cell, has been constructed to observe the mechanical deformation of the crystal lattice of polymers at cryogenic temperature. The polymer specimen could be cooled down to 18 K using this apparatus. The equatorial diffraction profiles of polymer specimens were observed under various temperatures and loads with 18 K minimum temperature. The equatorial lattice spacings of polyethylene (PE) decreased at 18 K compared with those at 300 K; however, they were elongated by a constant applied tensile stress. The elastic modulus Et of the crystalline regions of PE in the direction perpendicular to the chain axis was evaluated. The Et value for the (200) plane of PE increased to 11 GPa at 18 K from 3.2 GPa at 300 K. This is considered to be due to the increase of the van der Waals interactions between the chains in the crystal lattice at very low temperature, where the incoherent thermal vibrations of the atoms can be ignored. © 2002 American Institute of Physics.
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  • 3
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Zusammenfassung Isotaktisches, syndiotaktisches und ataktisches Polymethylmethacrylat wurden präpariert und fraktioniert und an den Fraktionen dieΘ-Temperaturen und Entropieparameterψ 1 in vier Lösungssystemen aus der Ausfällung bestimmt, sowie die Intrinsic-Viskositäten zwischen isotaktischen und ataktischen Modifikationen bei denΘ-Temperaturen verglichen. Es zeigt sich, daß die ungestörte Dimension und der Entropieparameter der isotaktischen Proben größer als das entsprechende der ataktischen ist. Auch wurde gefunden, daß die Temperaturabhängigkeit für die ungestörten Dimensionen für beide isomere Formen völlig verschieden ist. Die Moleküldimensionen der isotaktischen Modifikation im Medium ohne Wechselwirkung läßt sich in Übereinstimmung mit der Behandlung halbflexibler Ketten nachFlory formulieren.
    Notes: Summary Isotactic, syndiotactic and atactic polymethyl methacrylate were prepared by proper methods and fractionated. With these fractions, the theta temperatures and the entropy parameters,ψ 1, were determined in four solvent systems from the precipitation measurements, and the intrinsic viscosities were compared between isotactic and atactic modifications at the theta temperatures. It was pointed out that the unperturbed dimension and the entropy parameter of the isotactic species, respectively, are larger than those of the atactic species. Also, it was found that the temperature dependence of the unperturbed dimensions is quite different for both isomeric forms. The molecular dimensions of the isotactic modification in non-interacting media were interpreted in accordance with the semi-flexible chain treatment ofFlory.
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  • 4
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 611-618 
    ISSN: 0887-6266
    Keywords: elastic modulus ; crystalline regions ; cellulose triester ; crystal structure ; mechanical property ; hydrogen bond ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Elastic moduli of the crystalline regions of cellulose triesters in the direction both parallel El and perpendicular Et to the chain axis are measured by x-ray diffraction. El values for cellulose triesters are as follows: cellulose triacetate (CTA), 33.2 GPa; cellulose tripropionate (CTP), 21.6 GPa; cellulose tributyrate (CTB), 17.6 GPa; cellulose trivalerate (CTV), 17.9 Gpa. These are very small compared with that of cellulose I (134 GPa) and resemble each other despite the fact that the skeletal structure of CTP (32 helix) is much different from those of other cellulose triesters (2-fold helix). The small El values for cellulose triesters can be explained by both the large cross-sectional area of one molecule in the crystal lattice and the lack in intramolecular hydrogen bonds. Et values for cellulose triesters are as follows: CTA (310), 2.8 GPa; CTP (110), 1.4 GPa; (020), 2.1 GPa; (120), 2.2 GPa; CTB (110), 1.1 GPa. These are one of the smallest Et values already reported, and decrease with increasing the length of the side chain. Intermolecular interaction is considered to decrease with the length of acyl groups. The large Et value in the b direction of CTP reflects the dense packing of the chains in the crystal lattice. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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  • 5
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Protein adsorption on copolymer films having pendant monosaccharide groups was investigated from the viewpoint of surface chemistry. The copolymers were synthesized by the copolymerization of a monomer having a pendant monosaccharide (GEMA) and methyl methacrylate (MMA). The contact angles of methylene iodide and air bubble on the GEMA-MMA copolymer films were measured in water, and the surface free energy of the copolymer films in water was calculated from the contact angles. With increasing GEMA content, the amount of protein adsorbed on the GEMA-MMA copolymer films decreased gradually. The relationship between protein adsorption and the surface free energy of the copolymer films in water is discussed. The differences between surface free energy before and after protein adsorption on the copolymer surface is closely related to the amount of adsorbed protein.
    Additional Material: 8 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 197 (1996), S. 1135-1146 
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A glucose-sensitive hydrogel was prepared by introducing concanavalin A (Con. A) into poly(2-glucosyloxyethyl methacrylate) (poly(GEMA)) hydrogel. The decrease in swelling ratio and increase in crosslinking density by introduction of Con. A into the poly(GEMA) hydrogel indicate that the complexation introduces additional crosslinking points. The swelling of the hydrogel increased in the presence of glucose, and the swelling ratio was dependent on the glucose concentration. The glucose sensitivity of the hydrogel is attributable to the dissociation of the complex between poly(GEMA) and Con. A in the presence of glucose. Furthermore, the poly(GEMA)-Con. A complex hydrogel was responsive to the kind of monosaccharide; its swelling ratio was changed by the presence of glucose or mannose, but not by the presence of galactose. The swelling properties of this hydrogel might be useful for the development of a glucose-sensitive device.
    Additional Material: 11 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Rapid Communications 14 (1993), S. 413-420 
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 26 (1981), S. 1675-1679 
    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: Emulsifier-free emulsion polymerization of styrene in acetone-water medium was carried out using potassium persulfate as initiator. Below acetone content of 40 vol %, stable emulsion was prepared and polymerizations were remarkably fast compared with those in pure water. The particle size decreased from 0.5 to 0.17 μm with an increase in acetone content in the range 0-40 vol %, and the distributions were very sharp. The optimum polymerization for the preparation of the stable emulsion was: styrene, 20 vol %; acetone/water, 40/60 (v/v); KPS, 3.4 × 10-3 mole/l; temp., 90°C.
    Additional Material: 4 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 45 (1992), S. 1239-1244 
    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: Residual stress in particulate epoxy resin was investigated by X-ray diffraction. Microdeformation of incorporated Al and α-SiO2 crystal, which was induced by the residual stress, could be detected as a shift of X-ray diffraction peak. The residual stress at the interface between the adherend and the particulate epoxy resin was found to decrease with the increase of volume fraction of filler. It was shown that the difference in the thermal expansion coefficients between the adherend and the particulate epoxy resin is much more effective on residual stress than the increment of Young's modulus owing to the incorporation of filler. When epoxy resin was cured on the Al plate, incorporated particles were subjected to a tensile stress; while cured on polytetrafluoroethylene sheet, particles were subjected to a compressive stress. The incorporation of some inorganic particles is considered effective to reduce the residual stress.
    Additional Material: 7 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 1479-1489 
    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 mechanism of foam inhibition in an aqueous sodium dodecylbenzene sulfonate (DBSNa) solution by temperature-sensitive, water-soluble poly(dimethylaminoethyl methacrylate) (PDM) was investigated. The solution's foam collapsing rate, % transmittance, surface tension, pH, temperature, and degree of hydrophobicity of PDM showed that aging a PDM-DBS solution 125 to 280 hr produced a turbid solution and effectively inhibited foaming. Likewise, controlling the pH at 4 ≤ pH ≤ 7 and increasing the hydrophobicity of PDM enhanced the foam-inhibiting action of the polymer. The reaction between DBSNa and PDM was temperature dependent and the temperature effect was almost reversible. When compared with other available commercial antifoaming agents, PDM was found most effective in suppressing foam formation in aqueous DBSNa solution.
    Additional Material: 9 Ill.
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