Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Techniques are presented which result in the production of thromboresistant materials which can be used to interface with blood in the vascular system. Three useful processes for the heparinization of materials are presented and data are given on characteristics of attachment, the blood compatibility, and environmental stability of these surfaces. At this point, applications of heparinized surfaces via a simple one-step process should be limited to siturations where low blood shear rates are involved, such as the venous system. Intitial data indicate significant loss of surface heparin in situations where high blood flow rates are involved such as A-V shunts.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Für die Molekulargewichtsbestimmung von Nichtelektrolyten in der Ultrazentrifuge werden Gleichungen für den Virialkoeffizienten B und den Mittelwert M̄z+1 für zwei Kondensationspolymere abgeleitet. Das Verhältnis M̄z+1/M̄z wird 4/3 für A—B- und 10/3 für A—R—B2-Polykondensate. Für die apparenten Mittelwerte M̄z und M̄w ergibt sich für die Virialkoeffizienten die Beziehung Bz/Bw = 2 M̄w/M̄z.Verzweigte niedermolekulare Polymere, die aus „dentcorn“-Stärke isoliert waren, ergaben M̄z/M̄w = 2,9, während sich aus Bz/Bw der Wert 3,9 errechnet. Für die Komponenten am Zellenboden war M̄z,b/M̄w,b = 1,6, während dort aus Bz/Bw der Wert 2,0 folgt. Damit erklärt die theoretische Gleichung, warum Bz kleiner sein kann als Bw.
    Notes: Equations were developed for the concentration coefficient of a nonelectrolyte in ultracentrifugal molecular weight determinations and for the expected value of M̄Z+1 for both A—B- and A—R—B2-condensation polymers. The value of M̄Z+1/M̄Z is 4/3 for A—B-polymers and 10/3 for A—R—B2-polymers. The equations show that the concentration coefficient from the apparent Z-average molecular weight (Bz) divided by that from the apparent weight-average molecular weight (Bw) should be Bz/Bw = 2 (M̄w/M̄z). Data were obtained on a low-molecular-weight branched polymer isolated from dent corn starch. The values of M̄z/M̄w obtained from the extrapolated molecular weights for the entire sample and for the components at cell bottom (b) were M̄z/M̄w = 2.9 and M̄z,b/M̄w,b = 1.6, whereas the respective values of the ratio from Bz/Bw were M̄z/M̄w = 3.9 and M̄z,b/M̄w,b = 2.0. Hence, the theoretical equation Bz/Bw = 2 (M̄w/M̄z) explains why the value of Bz can be less than the value of Bw for heterogeneous polymers.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Two principally different mechanisms are discussed for the polymerisation of hydrogen cyanide. The one considers the building up of the polymer as being stepwise and based on hydrogen cyanide as the monomer, whereas the other one assigns the hydrogen cyanide dimer for being the actually polymerizing “monomer”. In the case of the “dimer polymerisation” a carbene mechanism is taken into consideration besides an anionic one.Different N-alkyl substituted hydrogen cyanide dimers were synthesized. They did not exhibit any properties of a carbene and were relatively stable. Their reactions with hydrogen cyanide were studied. A series of addition products were obtained which extensively favor the mechanism of the stepwise polymerisation.
    Notes: Für die Polymerisation der Blausäure werden zwei grundsätzlich verschiedene Mechanismen diskutiert, von denen einer den schrittweisen Aufbau des Polymeren, ausgehend von Blausäure als Monomerem, vorsieht, während der andere auf dem Dimeren der Blausäure als dem eigentlichen polymerisierenden „Monomeren“ beruht. Für die „Dimerpolymerisation“ wird neben dem anionischen noch ein carbenoider Mechanismus in Betracht gezogen.Es wurden verschiedene N-Alkyl-substituierte Blausäuredimere hergestellt. Sie zeigten keinen Carbencharakter und waren relativ stabil. Ihre Umsetzungen mit Blausäure wurden studiert. Dabei wurde eine Reihe von Additionsprodukten erhalten, die weitgehend den schrittweisen Polymerisationsmechanismus favorisieren.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1795-1799 
    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
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 57 (1995), S. 931-938 
    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: Electroinitiated polymerization coatings are uniform, thin, tightly adherent, conformal, and economical to produce. This article describes use of a novel (for electropolymerization) persulfate initiator to rapidly polymerize a moderate Tg crosslinked acrylic coating. Polymer coatings derived from the monomers acrylamide, acrylonitrile, and N,N′-methylenebisacrylamide were synthesized on an aluminum cathode by persulfate electroinitiated polymerization at room temperature. The crosslinked polymer was brittle (Tg = 239°C) but thermally stable (degradation temperature = 310°C). The coatings were spongy and contained some small cracks when polymerized at low current density (0.1 mA/cm2). However, thicker coatings with fewer cracks were obtained at higher current densities. Persulfate was found to be an effective initiator for polymerization in this system, and the initiation mechanism was confirmed to be free radical. In general, it appears possible to produce thin, uniform coatings on aluminum by this route. © 1995 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 0935-9648
    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
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Treatement with hydrazine was used to investigate the crystalline morophology of commercially drawn nylon 6,6 fibers. Electron microscopic investigation revealed a stacked lamellar structure for the debris of a highly oriented, rapidly drawn fiber. However, the high molecular weight range of the gel permeation chromatogram of this same oriented fiber indicated the presence of high molecular weight material. This is thought to be due to the production of rod-like, partially extended regions during drawing.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A technique for the selective degradation of amorphous regions in nylon 6,6 is reported. Samples of unoriented film and single-crystal mats have been subjected to selective degradation by refluxing in hydrazine. Weight loss, viscosity-average molecular weight, density, and small-angle x-ray scattering of these samples were monitored as a function of time of degradation. In addition, selected samples have been investigated by gel permeation chromatography (GPC) and transmission electron microscopy. Based on the results of these investigations it is concluded that the reported degradation technique is unique in that the debris is not monodisperse in molecular weight distribution. The Weight loss, density, small-angle x-ray scattering, and microscopy data demonstrate that the unordered or noncrystalline regions of the material are removed upon treatement. However, the relatively high molecular weight and broad molecular weight distribution of the debris indicate that regular folds at lamellar surfaces are intact after degradation treatment.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Quantitative Hv small-angle light-scattering (SALS) studies of the melting of poly(ethylene terephthalate) (PET) have been performed. The results are compared with those from differential scanning calorimetry (DSC). It is found that fully grown spherulites melt over a temperature range of about 20°C without change in spherulite size, number, or internal disorder. The decrease in Hv SALS intensity is due to a decrease in spherulitic crystallinity over the melting range. The corrected experimental intensities are lower than, but in reasonable agreement with, the theoretically predicted intensities based on the DSC results. Procedures are presented for the quantitative analysis of Hv SALS intensities from spherulitic systems, including the corrections for the experimental, external disorder, and internal disorder effects.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...