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  • Polymer and Materials Science  (33)
  • FLUID MECHANICS AND HEAT TRANSFER  (8)
  • 1
    Electronic Resource
    Electronic Resource
    pH responsive microdomain formation in a De Novo polypeptide (1997)
    New York : Wiley-Blackwell
    Biopolymers 41 (1997), S. 521-532 
    Details
    ISSN: 0006-3525
    Keywords: recombinant DNA ; pH responsive hydrophobic microdomains ; dn31 gene ; gel filtration chromatography ; CD ; fluorescence probe analysis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Recombinant DNA technology has been employed to produce a polypeptide capable of forming pH responsive hydrophobic microdomains. The design of this peptide is based upon an idealized conceptual model in which electrostatic, hydrophobic, and hydration forces are responsible for the association of amphipathic α-helical elements. Reduction in solution pH is responsible for reducing electrostatic repulsions between similarly charged residues, promoting the hydrophobic collapse of helical elements. A polymerizable synthetic element (dn31) has been synthesized and inserted into an appropriate expression vector. A clone containing a single copy of the dn31 gene (designated dn31x1) was isolated and the corresponding gene product DN3Lx1 isolated. The physical properties of DN3Lx1 were examined in solution by gel filtration chromatography, CD, and fluorescence probe analysis. It was determined that DN3Lx1 self-associates in solution with the degree of aggregation dependent on pH and ionic strength. An initial objective of this work was to examine domain organization in higher molecular weight species containing ten or more repetitive sequences. However, attempts to express multiple repeats of DN3Lxn from concatemers were unsuccessful. © 1997 John Wiley & Sons, Inc. Biopoly 41: 521-532, 1997.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Water-soluble copolymers, 16Part 15, cf. B. H. Hutchinson and C. L. McCormick, Polymer 27, 623 (1986).. Studies of the behavior of acrylamide/N-(1,1-dimethyl-3-oxobutyl)acrylamide copolymers in aqueous salt solutions (1987)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 357-370 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The behavior of N-(1,1-dimethyl-3-oxobutyl)acrylamide more commonly known as diacetone acrylamide (DAAM) polymers and acrylamide/diacetone acrylamide copolymers in aqueous and non-aqueous solutions has been examined. 13C NMR and IR studies do not support the formation of a six-membered hydrogen-bonded ring structure in the DAAM moiety as an explanation of the unusual increase in solution viscosity shown by these copolymers upon addition of salt. A 12-membered hydrogen-bonded structure involving the diacetone acrylamide side chain and an adjacent acrylamide unit is proposed which is consistent with the available data and which would explain the viscosity behavior. Another possible structure involves hydrogen bonding between adjacent comonomers through amide/imine resonance structures. Copolymer microstructure as indicated by calculated pentad and triad frequencies supports either of these proposed structures.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1987.021880213
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  • 3
    Electronic Resource
    Electronic Resource
    Water-soluble copolymers. I. Synthesis of model dextran-g-polyacrylamides by Fe(II)/H2O2 initiation and characterization by aqueous size exclusion chromatography (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 26 (1981), S. 1705-1717 
    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: Model graft copolymers were synthesized by grafting acrylamide onto dextran (M̄w = 500,000) utilizing the Fe(II)/H2O2 initiation system. Aqueous size exclusion chromatography (SEC) was used to determine the effects of changing reaction parameters on hydrodynamic dimensions of the resulting graft copolymers. It was also possible to optimize reaction conditions yielding the highest viscosity graft copolymer with the least amount of homopolyacrylamide and unreacted substrate. The molecular structures of the graft copolymers were determined by elemental analysis, SEC, and solution viscometry. Selective hydrolysis of the dextran backbone allowed determination of average molecular weight of acrylamide grafts, number of grafting sites, and average molecular weight of the graft copolymers. Rheological studies indicated viscosity and pseudoplastic behavior were largely related to the graft length of the polyacrylamide side chains.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1981.070260525
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  • 4
    Electronic Resource
    Electronic Resource
    Water-soluble copolymers. XIII. Copolymers of acrylamide with sodium-3-acrylamido-3-methylbutanoate: Solution properties (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 2619-2634 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dilute solution properties of copolymers of acrylamide (AM) with sodium-3-acrylamido-3-methylbutanoate (NaAMB) of known molecular weight have been studied as a function of composition, temperature, time, pH, and added electrolytes. Phase separation and potentiometric studies have also been performed. The AM-NaAMB copolymers exhibit high solution viscosities, good salt tolerance, and moderate viscosity-temperature coefficients. In addition, these copolymers exhibit no phase separation in the presence of divalent cations as is common with many such carboxylated polyelectrolytes. These properties are due to favorable conformations in solution resulting from microstructure and hydrogen bonding effects.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080241019
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  • 5
    Electronic Resource
    Electronic Resource
    Water-soluble polymers. 72. Synthesis and solution behavior of responsive copolymers of acrylamide and the zwitterionic monomer 6-(2-acrylamido-2-methylpropyldimethylammonio) hexanoate (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 243-253 
    Details
    ISSN: 0887-624X
    Keywords: polyampholyte ; polycation ; zwitterionic ; water soluble ; carboxy betaine ; acrylamide copolymers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel carboxybetaine monomer, 6-(2-Acrylamido-2-methylpropyldimethylammonio) hexanoate (AMPDAH), has been synthesized and copolymerized with acrylamide in an aqueous NaBr solution. The feed ratio of AM (M1): AMPDAB(M2), was varied from 98.5 : 2.5 to 0 : 100 mol %. The polymerizations were carried out to 20-30% conversion. Copolymer compositions were determined with 13C NMR by integration of the amido carbonyl resonances. Reactivity ratios determined from the nonlinear least-squares method gave values of r1 = 0.98 and r2 = 0.85, indicating random incorporation of the comonomers into the final copolymer. Molecular weights ranged from 7.3 to 4.7 × 106 g/mol. The solubility behavior of the copolymers is dependent on the mol % AMPDAH incorporated into the copolymers. When 25 mol % or more is incorporated, the copolymers are only swellable in aqueous media and attempts to solubilize these systems were unsuccessful. AMPDAH incorporation of 10 mol % or less resulted in copolymers soluble in aqueous media under a variety of conditions. The viscometric properties of copolymers with 10 mol % or less is reported as a function of pH and added electrolytes. At high pH in deionized water, the polyzwitterions show both inter- and intramolecular associations, which are disrupted by the addition of sodium chloride. In deionized water, as the pH of the aqueous medium is lowered, the copolymers exhibit dramatic increases in viscosity as the carboxylate groups are protonated and charge-charge repulsions of the quaternary ammonium groups induce polyelectrolyte behavior. © 1997 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Water-soluble copolymers. XII. Copolymers of acrylamide with sodium-3-acrylamido-3-methylbutanoate: Synthesis and characterization (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 2635-2645 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The copolymerization of acrylamide (AM) with sodium-3-acrylamido-3-methylbutanoate (NaAMB) has been studied. The value of r1r2 has been determined to be 0.56 for the AM-NaAMB pair. The molecular weights of the copolymers were relatively unaffected by monomer feed ratios. The copolymer microstructures, including run numbers and sequence distributions, were calculated from the reactivity ratios. The solution properties of the AM-NaAMB copolymers, as well as the NaAMB homopolymer, will be reported in a subsequent paper.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080241020
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  • 7
    Electronic Resource
    Electronic Resource
    Water-soluble copolymers. XXV. Ion-binding studies of N-substituted acrylamide copolymers using potentiometric and spectroscopic methods (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 25 (1987), S. 1329-1337 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Spectroscopic and potentiometric methods have been used to study the ionic properties of several N-substituted acrylamide copolymers that display unusual ion-binding character. The ionic groups and the amide groups (both on the same repeating unit and on adjacent acrylamide units) in the copolymers are found to chelate calcium ions. The stabilizing effect of this amide chelation is found to be dependent on copolymer composition. A model is proposed to explain the unusual binding behavior of the acrylamide polymers. This involves the formation of an intramonomer chelate or one with neighboring acrylamide units that prevent precipitation of the polymers.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1987.080250511
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  • 8
    Electronic Resource
    Electronic Resource
    Water-soluble copolymers. XLII. Cationic polyelectrolytes of acrylamide and 2-acrylamido-2-methylpropanetrimethylammonium chloride (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 1099-1104 
    Details
    ISSN: 0887-624X
    Keywords: polyelectrolyte ; polycation ; acrylamide ; water soluble ; phase stability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The new monomer 2-acrylamido-2-methylpropanetrimethylammonium chloride (AMP-TAC, M2) has been synthesized. Free radical copolymerization with acrylamide (AM, M1) in feed ratios varying from 10 to 50 mol % AMPTAC gave the cationic ATAM series. Copolymer compositions were determined from 13C-NMR. The reactivity ratio product r1r2 was found to be 0.62. Molecular weights varied from 1.4 to 16.5 × 106 g/mol for the copolymers. Turbidimetric studies showed aqueous solutions of the copolymers to be phase stable in the presence of CaCl2 and Na2CO3 up to 100°C. Solution behavior was independent of pH in the range of 3 to 11, and temperature in the range of 25 to 60°C. Intrinsic viscosities of the cationic copolymers decreased with the addition of electrolytes; however, some samples showed curvature in plots of intrinsic viscosity versus the inverse square root of ionic strength. © 1993 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080310501
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  • 9
    Electronic Resource
    Electronic Resource
    Perspective: Comments on “recent developments in polymerization by an alternating intra-intermolecular mechanism,” by George B. Butler, J. Polym. Sci., XLVIII, 279 (1960) (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 911-912 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1996.820
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  • 10
    Electronic Resource
    Electronic Resource
    Copolymerization kinetics of a model siloxane system (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 1293-1302 
    Details
    ISSN: 0887-624X
    Keywords: methylethoxysilanes ; hydrolysis ; polycondensation ; sol-gel ; modeling ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using 29Si NMR, we monitor the copolymerization of trimethylethoxysilane and dimethyldiethoxysilane (model compounds for more complex sol-gel copolymer systems) in a batch reactor. Under the chosen conditions, the extents of self- and cross-condensation reactions are readily determined. Using a nonideal polycondensation kinetic model, we show that the copolymerization rate coefficient for a pair of sites of differing functionality is bounded by their homopolymerization rate coefficients, lying closer to the larger one. This reactivity pattern generates a heterogeneous monomer distribution in the copolymerization products. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1293-1302, 1997
    Additional Material: 3 Ill.
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