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  • 1
    Electronic Resource
    Electronic Resource
    In situ observation of surface deformation of polymer films by atomic force microscopy (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 2094-2096 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1150585
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  • 2
    Electronic Resource
    Electronic Resource
    X-ray diffraction of polymer under load at cryogenic temperature (2002)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 73 (2002), S. 1809-1812 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1453501
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  • 3
    Electronic Resource
    Electronic Resource
    Conformation of polymethyl methacrylate stereochemical isomers in non-interacting media (1962)
    Springer
    Colloid & polymer science 186 (1962), S. 41-50 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01797952
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  • 4
    Electronic Resource
    Electronic Resource
    Preparation and catalytic action of an asymmetric ethylene/vinyl alcohol copolymer-copper complex membrane (1992)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 193 (1992), S. 2737-2749 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An ethylene/vinyl alcohol copolymer (EVA)-copper complex membrane was prepared by casting an EVA-CuCl2 mixture (solvent: water-propanol (1:1 v/v) mixture) on a polyethylene substrate and then immersing it in 0,1 M KOH aqueous solution. In the membrane, Cu was distributed asymmetrically in the direction of the membrane cross section. The distribution of Cu could be controlled by the temperature during preparation. The oxidation of hydroquinone during permeation through the complex membrane was performed using membranes with different Cu distribution. This distribution influences the permeation reaction. These results are well reproduced by a relation composed of Fick's law and Michaelis-Menten type reaction kinetics. Therefore, a good reactor can be developed by controlling the catalyst distribution.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1992.021931103
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  • 5
    Electronic Resource
    Electronic Resource
    Swelling behavior of hydrogels containing phosphate groups (1992)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 193 (1992), S. 983-990 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Hydrogels containing phosphate groups were prepared by copolymerization of 2-methacryloyl-oxyethyl dihydrogen phosphate (phosmer) and various hydrophilic monomers [N,N-dimethyl-acrylamide (DMAAm), acrylic acid (AAc) and 2-hydroxyethyl methacrylate (HEMA)], and the swelling behavior was investigated. These hydrogels are thermo-sensitive. Phosmer-DMAAm and phosmer-HEMA hydrogel deswell with increasing temperature, but for the phosmer-AAc hydrogel the swelling ratio increases with temperature. Interestingly, the swelling ratio decreases with an increase in phosphate group content. This unusual behavior may arise from the phosphate group acting both as the functional group and the crosslinking agent.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1992.021930414
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  • 6
    Electronic Resource
    Electronic Resource
    Stimuli-sensitivities of hydrogels containing phosphate groups (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 195 (1994), S. 1111-1120 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of an introduction of phosphate groups into hydrogels on their stimuli-sensitivities has been investigated. Several hydrogels containing various phosphate group content were synthesized via solution copolymerization of 2-(methacryloyloxy)ethyl dihydrogen phosphate (Phosmer) and 2-hydroxyethyl methacrylate (HEMA) in the presence of 2,2′-azoisobutyronitrile (AIBN) in methanol at 70°C for 4 h. The content of phosphate groups incorporated into the resulting hydrogels ranged from 1 to 13 mol-%. The swelling ratio of these hydrogels was found to be strongly affected by pH, solvent, temperature and phosphate group content. The polymersolvent interaction parameter χ of the hydrogel was determined from the Flory-Rehner equation, using the swelling ratio and the crosslinking density derived from the compression modulus. Furthermore, χ was divided into its enthalpic (χH) and entropic component (χS). Using the interaction parameter, the stimuli-sensitivity of the hydrogel is discussed in detail based on thermodynamic aspects.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1994.021950401
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  • 7
    Electronic Resource
    Electronic Resource
    Surface characterizations of copolymer films with pendant monosaccharides (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 195 (1994), S. 1953-1963 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We copolymerized a monomer with a pendant glucose unit (GEMA) with methyl methacrylate (MMA) and prepared copolymer films with pendant monosaccharides by casting the copolymer solution on glass plates. The surfaces of the copolymer films were characterized by contact angle measurements, X-ray photoelectron spectroscopy (XPS) and protein adsorption measurements, and compared with the surface of 2-hydroxyethyl methacrylate (HEMA)-MMA copolymer films. The surface free energy of the GEMA-MMA and HEMA-MMA copolymer was calculated from the contact angle of methylene diiodide and glycerol on the copolymer films. The surface free energy of the films increased gradually with increasing GEMA or HEMA content. The surface free energy of GEMA-MMA copolymers was larger than that of HEMA-MMA copolymers in the whole range of composition. The results of XPS measurements suggest that the fraction of GEMA at the copolymer surface increases as the content of GEMA in the copolymer increases. This indicates that introduction of GEMA makes the copolymer surface more hydrophilic. Further more, the higher the GEMA content is, the smaller amounts of fibrinogen and γ-globulin are adsorbed at the copolymer surface. The copolymer with a GEMA content of 20 mol-% hardly adsorbs fibrinogen and γ-globulin at all.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1994.021950606
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  • 8
    Electronic Resource
    Electronic Resource
    Preparation of poly(2-glucosyloxyethyl methacrylate)-concanavalin A complex hydrogel and its glucose-sensitivity (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 197 (1996), S. 1135-1146 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1996.021970330
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  • 9
    Electronic Resource
    Electronic Resource
    Elastic modulus of the crystalline regions of cellulose triesters (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 611-618 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1995.090330411
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  • 10
    Electronic Resource
    Electronic Resource
    Protein adsorption on a copolymer having pendant monosaccharide groups. Relationship between surface free energy and protein adsorption (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 195 (1994), S. 3597-3607 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1994.021951107
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