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  • 1
    Electronic Resource
    Electronic Resource
    Preparation and properties of copolymers of methyl-2,3,3-trifluoroacrylate with alkenes and alkyl vinyl ethers (1986)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 141 (1986), S. 131-139 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Durch eine mit Diisopropoxycarbonylperoxid initiierte radikalische Lösungspolymerisation wurden Copolymere von Methyl-2,3,3-trifluoracrylat mit Isobutylen, Propylen, Ethylen und n-Alkylvinylethern (wobei Alkyl Ethyl, Propyl oder Butyl bedeutete) hergestellt. Die Struktur der Copolymeren entspricht einer alternierenden Zusammensetzung der Methyltrifluoracrylat- und Comonomer-Einheiten. Die Polymerisationsgeschwindigkeit und die Molekulargewichte sind durch das Verhältnis der beiden Monomeren und durch die Art des Vinylmonomeren bedingt. Die alkalische Hydrolyse der Trifluoracrylateinheiten liefert Copolymere der Trifluoracrylsäure. Der Dissoziierungsgrad der Copolymeren wird durch den pK-Wert charakterisiert. Die Hydrolysegeschwindigkeit ist stark von der Struktur des Copolymeren abhängig. Die Polymeren sind gut beständig gegen höhere Temperaturen, und eine thermische Zersetzung erfolgt erst bei über 300°C.
    Notes: Copolymers of methyl-2,3,3-trifluoroacrylate with isobutylene, propylene, ethylene, and n-alkyl vinyl ethers, (the alkyl being ethyl, propyl, butyl) glycidyl vinyl ether, and 2-methoxyethylvinyl ether were prepared by radical solution polymerization using di(isopropoxycarbonyl) peroxide as the initiator. Their structure was that of the alternating order of methyltrifluoroacrylate and the respective vinyl monomer units. The rate of copolymerization and molecular weights of the copolymers were determined by the ratio of both monomers and by the character of the vinyl comonomer. By means of the alkaline hydrolysis of trifluoroacrylate units, the corresponding copolymers of trifluoroacrylic acid were prepared. Their degree of dissociation was characterized by pK values. The rate of alkaline hydrolysis was considerably affected by the copolymer structure. The polymeric materials prepared in this study possessed good thermal stability, and their thermal decomposition did not occur below 300°C.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1986.051410113
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  • 2
    Electronic Resource
    Electronic Resource
    Preparation and properties of dialysis membranes prepared from a ternary solution of cellulose acetate/acetone/dimethylformamide (1985)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 132 (1985), S. 187-195 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurden Dialysemembranen durch Gießen von Celluloseacetatlösung in ein Lösungsmittelgemisch von Aceton/Dimethylformamid (1 : 1) und durch teilweises Abdampfen des Lösungsmittels von der gegossenen Lösung bei Raumtemperatur und durch Koagulieren in Eiswasser hergestellt. Der Einfluß der Polymerkonzentration in der Lösung und der Abdampfdauer des Lösungsmittels auf die Zugfestigkeit, Morphologie und Permeabilität der Membranen wurde untersucht. Membranen mit den besten mechanischen Eigenschaften wurden aus Lösungen von 20-28 Gew.-% Celluloseacetat bei Abdampfzeiten über drei Minuten gebildet. Diese Membranen enthielten ein Minimum an Hohlräumen in ihren unteren Schichten. Die Permeabilität der Membranen für niedermolekulare Stoffe steigt mit sinkender Polymerkonzentration in den Lösungen und mit Verlängerung der Abdampfdauer des Lösungsmittels bis zu ungefähr 2 Minuten an.
    Notes: Dialysis membranes were prepared by casting a solution of cellulose acetate in a mixed solvent acetone/dimethylformamide (1:1) followed by partial evaporation of the solvent from the cast solution at room temperature and by coagulation in icewater. The effect of the polymer concentration in solution and evaporation time of the solvent on tensile strength, morphology, and permeability of the membranes was investigated. Membranes possessing the best mechanical properties are formed from solutions containing 20-28 wt.-% cellulose acetate and at evaporation times longer than three minutes. The membranes contain the minimal amount of cavities in their lower layer. The permeability of the membranes for low molar mass compounds increases with decreasing polymer concentration in the casting solution and with extension of the evaporation time of the solvent up to ca. 2 min.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1985.051320114
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  • 3
    Electronic Resource
    Electronic Resource
    The role of water at the permeation of non-electrolytes through hydrophilic membranes (1987)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 38 (1987), S. 196-199 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Transporteigenschaften partiell hydrophiler Ionenaustauschermembranen für Wasser und hydroxylgruppenhaltige Nichtelektrolyte wurden bestimmt. Durch Einführung fraktioneller Diffusionskoeffizienten im „freien“ und „strukturierten“ Wasser in der Matrix können die Ergebnisse interpretiert werden. Mathematische Beziehungen zwischen dem Volumenanteil des Wassers und dem Diffusionskoeffizienten sowie eine Gleichung für den Anteil des „freien“ Wassers wurden abgeleitet.
    Notes: Transport properties of partial hydrophilic ion-exchange membranes have been determined for water and hydroxyl group containing non-electrolytes. Interpretation of the results is possible by introduction of fractional diffusion coefficients in “free” and “structural” water of the matrix. Mathematical relations between volume fraction of water and diffusion coefficients as well as an expression for the fraction of “free” water are derived.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1987.010380309
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  • 4
    Electronic Resource
    Electronic Resource
    Deformational, swelling, and potentiometric behavior of ionized gels of 2-hydroxyethyl methacrylate-methacrylic acid copolymers (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 2073-2082 
    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 deformational, swelling, and potentiometric behavior of ionized water-swollen gels of 2-hydroxyethyl methacrylate (HEMA)-methacrylic acid (MA) copolymers used in biomedical and separation applications was investigated. With increasing degrees of neutralization α, the swelling degree strongly increases and the modulus Gs decreases. For the copolymers with MA content ≥ 30 mole-%, the dependence of Gs on α passes through a minimum. Comparison of the results with the modified theory of rubber elasticity shows that the decrease in Gs at low concentrations of charges on the chain is controlled mainly by the degree of swelling. At higher α, both the finite extensibility of network chains, caused by a high degree of swelling, and electrostatic interactions contribute to Gs. The dependence of the interaction parameter χ on the volume fraction of polymer in the gel, v2, is independent of α and closely resembles the dependence obtained for other hydrophilic polymers.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070230717
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  • 5
    Electronic Resource
    Electronic Resource
    Specific resistances of hydrophilic membranes containing ionogenic groups (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 3029-3044 
    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: This paper deals with an investigation of the dependence of specific resistances on pH for hydrophilic membranes containing ionogenic groups. Membranes based on poly(2-hydroxyethyl methacrylate) crosslinked with ethylene dimethacrylate were investigated. This basic structure was modified by copolymerization with ionogenic comonomers, i.e., methacrylic acid and/or diethylaminoethyl methacrylate. It is shown that the dependence of the specific resistance on pH passes through a maximum for cation-active membranes at pH ∼ 3.5, for anion-active membranes at pH ∼ 10, and for ampholytic membranes at pH ∼ 6. The effect of the content of ionogenic groups, network density, and the degree of neutralization of membranes on the above dependence is discussed. In the final part of the paper the results are compared with more hydrophilic systems based on poly(2-hydroxyethyl acrylate) and it is shown that maxima in the dependence of specific resistances on pH can be suppressed by increasing the hydrophilicity of polymers.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070191108
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  • 6
    Electronic Resource
    Electronic Resource
    Permeability of heterogeneous membranes based on methacrylic acid (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 2245-2251 
    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 permeability of H+, Na+, insulin, and hemoglobin through porous membranes made of crosslinked poly(methacrylic acid) was investigated at different pH values on both sides of the membrane. It was shown that a change in the charge of the protein during its transport through the membrane might raise the driving force of the process so much that the permeability coefficient of the protein through the membrane would be higher than in solution. In the case reported here, the flow of the protein may be regarded as partial electrophoresis in a porous medium.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070230803
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  • 7
    Electronic Resource
    Electronic Resource
    The surface treatment of polypropylene molds and its effect on the quality of cast contact lenses (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Biomaterials 3 (1992), S. 275-279 
    Details
    ISSN: 1045-4861
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: An investigation of the surface by XPS photoelectron spectroscopy has shown that the process of production of cast contact lenses based on poly(2-hydroxyethyl methacrylateco-diethyleneglycol methacrylate) is accompanied by mass transfer at the lens-mold boundary. This phenomenon, which impairs the compatibility of the lens during its application, can be considerably suppressed by employing a suitable surface modification of polypropylene molds. The surface treatment consisting in the oxidation of the mold surface by an AC corona discharge in the oxygen atmosphere increased hydrophilicity of the material, thus facilitating separation of the lens from the mold. The results of the XPS study were also confirmed microscopically by employing the SEM method. © 1992 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jab.770030406
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  • 8
    Electronic Resource
    Electronic Resource
    Biological tolerance of poly(N-substituted acrylamides) (1973)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 7 (1973), S. 111-121 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The biological tolerance of poly(N-substituted acrylamides) implanted subcutaneously to rats and pigs was investigated. Besides a macro- and microscopical evaluation of the implant and its surroundings, the surface changes of the implants were determined by means of a Stereoscan electron-optical microscope;the results obtained confirmed the very good in vivo stability of the polymers used.The histological analysis showed that all the polymers under investigation are very well tolerated by the organism and do not provoke any unfavorable reaction. The implants become surrounded with a granulation tissue which is gradually replaced by fibrocytes and collagen fibers situated in the basic substance staining positively with the alcian blue and PAS. In contrast with some authors we did not find a thicker capsule surrounding the implant on the sharp edges but on the flat planes. No calcification could be observed within the intervals investigated. The surface changes, which were studied electronoptically, were insignificant and connected with the way in which the implant was treated. No indications of malignant growth were observed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820070109
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  • 9
    Electronic Resource
    Electronic Resource
    Biological tolerance of ionogenic hydrophilic gels (1973)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 7 (1973), S. 123-136 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The long-term biological tolerance of hydrophilic gels containing ionogenic groups was investigated on animals (rats and pigs). The basic polymeric skeletons of poly(glyco1 monomethacrylate) and poly (N-ethyl methacrylamide) were modified by introducing acidic (carboxylic) and basic (tert-amino) groups, or both groups at a time. Introduction of both groups at a time in the molar ratio yielded an electroneutral polymer of ionogenic character.In all groups investigated here the implant was encapsulated by a fine capsule of collagen fibrous tissue; no signs of proliferation were observed. No calcification took place.The second part of the work consisted in an investigation of the tolerance of heterogeneous poly(glyco1 monomethacrylate) gels containing ionogenic groups,basic, acidic, and ampholytic, with continuously changing porosity. The microporous polymers (50-60% water in the starting mixture) were healed-in as compact gels by encapsulation with collagen fibrous tissue. The macroporous polymers (70% of water and more in the starting mixture) were encapsulated with a capsule of collagen fibrous tissue, from which newly formed capillaries,serous exudate and numerous cells penetrated into the implant. The more porous the material, the broader the zone of cellulization. In microporous polymers there was no calcification; in macroporous, calcification occurred in the margin of the implant or in its center. In contrast with other authors' findings,no effect of the chemical composition within the concentration range investigated upon the way of healing-in or calcification could be observed; only the effect of physical factors was evident.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820070110
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  • 10
    Electronic Resource
    Electronic Resource
    Biological tolerance of poly(N-substituted methacrylamides) (1971)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 5 (1971), S. 197-205 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Experiments were investigated on animals' biological tolerance of the copolymers of N-substituted methacrylamides with the monomers which can be considered for uses in the modification of the monomeric backbone. The group of N-substituted methacrylamides is the second one in the series of hydrophilic polymers arranged according to their increasing resistance to hydrolysis, and it follows immediately after the esters of methacrylic acid. Histological analysis has shown that the copolymer of N-ethyl methacrylamide with methyl methacrylate is the best tolerated polymer of this group. In the case of copolymers with butyl acrylate and butyl methacrylate, in the first days after implantation a stronger and more cellular capsula was formed, and an inflammation was observed in the surroundings of the encapsulated implant. Starting from day 30, however, no differences are found in the encapsulation, and the result of healingin of all the polymers is always favorable. No cancerogenic effects were observed; calcification was found only sporadically in the case of the copolymer with butyl methacrylate.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820050307
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