Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1975-1979  (11)
  • 1
    Electronic Resource
    Electronic Resource
    β-Structure Formation and Its Stability in Aqueous Solutions of α-L-Glutamic Acid Oligomers (1977)
    s.l. : American Chemical Society
    Macromolecules 10 (1977), S. 720-721 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma60057a052
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Spin Labeling of Ion Exchange Membranes (1976)
    s.l. : American Chemical Society
    Macromolecules 9 (1976), S. 186-188 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma60049a030
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Kinetics of γ-benzyl-L-glutamate NCA's polymerizations and molecular-weight distributions on corresponding polymers (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 2185-2199 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of γ-benzyl-L-glutamate NCA's polymerizations in dioxane as solvent are discussed. The partial orders respective to [A], the NCA concentration and [I0], the initial initiator concentration are given; the rate constants are deduced and a mechanism is proposed to justify a rate of polymerization Vp = k[A][I0]2.The dependence of the rate constants on the conformation of the growing chains is demonstrated; the acceleration is attributed to the ordered structures favorable to hydrogen bonding. The kinetics of aging have also been examined and discussed; it is shown that they cannot modify the kinetics of polymerization.The DPn were obtained on the same samples before and after debenzylation; it is proved that at any concentration, DPn ≃ [A0]/[I0].The molecular-weight distributions were obtained by chromatography and a polydispersity lower than 1.3 was deduced for each sample. The trimodal distribution, appearing as soon as [A0]/[I0] is larger than 3, is attributed to the existence of the three structures σ, β, and α. The weight fraction of each of the structures was correlated to the kinetics of polymerization.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1976.360151107
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Preparation and characterization of α-L-glutamic acid oligomers (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 2035-2048 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation and characterization of α-L-glutamic acid oligomers with degree of polymerization (DP) up to 12 are described. The preparation of polymers with low DP corresponding to various A/I ratios (where A and I are monomer and initiator concentrations, respectively) with end groups blocked is given. The conditions of the fractionation, which separates the different oligomers by ion-exchange chromatography, are discussed. Finally, the isolation from salt solutions of the pure acidic form is given. Each polymer obtained for a given A/I is characterized at the end of the polymerization by its molecular-weight distribution. The average DP values calculated are compared to the A/I values; agreement is very good. Potentiometric behaviour during neutralization is obtained as a function of the degree of polymerization and the elaboration of the polyelectrolytic phenomenon is discussed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360141005
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Local order in polyelectrolytic solutions detected by magnetic birefringence measurements on the (Tyr-Glu)n copolymer (1979)
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 101-111 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The local electrostatic order in polyelectrolytic solutions has been studied by magnetic birefringence measurements on short segments (n ∼ 34) of the (Tyr-Glu)n polypeptide in high magnetic fields up to 13 T. We give evidence that only above a critical polymer concentration do small domains exist within which the polymers show a parallel ordering. This structural order disappears suddenly at ionic strengths above about 5 × 10-2 M and above a melting temperature of about 50°C.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1979.360180110
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Potentiometric Studies on Interactions of α-L-glutamic Acid Oligomers with Cu(II) in aqueous Solutions (1979)
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 2341-2351 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four oligomers of α-L-glutamic acid with ends blocked by nonionizable protecting groups were studied in 0.1M NaClO4 solution using potentiometric measurements. The titrations were analyzed using a pit-mapping method. The results are compared with those obtained with the corresponding polymer. The successive dissociation constants of the carboxylic side chains are obtained for oligomers with degrees of polymerization varying from 1 to 6. Then the successive stability constants corresponding to the association Cu2+-oligomer are given, and the MpHqLr distribution is calculated for each oligomer introducing MHqL complexes.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1979.360180920
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Polyelectroyte behavior of a bacterial polysaccharide from Xanthomonas campestris: Comparison with carboxymethylcellulose (1978)
    New York : Wiley-Blackwell
    Biopolymers 17 (1978), S. 2663-2678 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The main physicochemical properties of the polysaccharide called Xanthan produced by Xanthomonas compestris are discussed: the activity coefficient of the counter-ion, the pK(α), and the ionic selectivity are investigated and compared to those of a carboxymetholcellulose. The weight-average molecular weight (Mw = 2 × 106), the intrinsic viscosity and the constant of sedimentation are determined as a function of the ionic strength. It is proved that in dilute solution, there is no intermolecular association, whatever the ionic strength. The conformation is proposed to be a rigid rodlike molecule whose length is 6000 Å, independent of ionic strength 〉 10-2N.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1978.360171113
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Polyelectrolyte behavior of carrageenans in aqueous solutions (1979)
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 1673-1683 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Osmotic coefficients of sodium, potassium, and calcium counterions have been determined in aqueous solutions on kappa-, iota-, and lambda-carrageenans at 25°C. The experimental results are correlated with the calculated ones from the limiting law of Manning. An orderd secondary structure exists in kappa- and iota-carrageenans. Its stability is discussed as a function of temperature, ionic strength, and the nature of the counterions.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1979.360180707
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Interchain correlation observed in neutron-scattering experiments on poly(α-L-glutamic acid) solutions (1977)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 15 (1977), S. 411-415 
    Details
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1977.130150705
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Application of gel permeation chromatography to polyelectrolytes: Salt rejection mechanism and molecular-weight distribution (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 17 (1979), S. 673-681 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Gel permeation chromatography (GPC) of polyelectrolytes in dimethylformamide (DMF) is studied. Three methods of monitoring elution (conductimetry, viscosimetry, refractometry) are used to investigate the molecular-weight distribution and, independently, the chemical composition expressed in terms of the ionic charge density as a function of the chain length in two copolymers of acrylonitrile and sodium methallylsulfonate. The distribution on the gel of the neutral salt NaNO3 added to the DMF and used for elution is discussed in terms of Donnan exclusion; in addition, it is concluded that to obtain the correct molecular-weight distribution, GPC measurements must be performed with an eluent containing a neutral salt at a concentration at least 5 × 10-2M to prevent electrostatic exclusion. The main difficulty in reaching rigorous conclusions comes from the dependence of the calibration curve on the salt composition of the eluent owing to interactions - dependent on the quality of the solvent - between the polystyrenes used as standards and the porous silica gel. Nevertheless, this perturbation is small and the agreement between the average molecular weights obtained by GPC and by direct determination is good and indicates that the universal calibration proposed for neutral polymers is also valid for polyelectrolytes.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.180170410
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...