Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • 1970-1974  (15)
  • Polymer and Materials Science  (15)
Materialart
Erscheinungszeitraum
Jahr
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 3033-3047 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Molecular weight distributions and molecular aggregation for poly(vinyl chloride) (PVC) polymerized in bulk at -10, -30, and -50°C have been measured using gel permeation chromatography. The aggregate content in PVC polymerized at -50°C was found to be 87 wt-%. These spherical aggregates of mean diameter of 5000 A are formed preferentially from PVC chains having high molecular weights and long syndiotactic sequence lengths. A temperature of 200°C was used to disintegrate these aggregates into single PVC molecules. In disagreement with measurements of Mn and Mw published in the literature, our measured values do not reach a minimum but rather increase continuously with decreasing temperature of polymerization. This disagreement is most probably due to the phenomenon of molecular aggregation in PVC.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 14 (1970), S. 1519-1529 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Equations developed for correcting Mn, Mw, and [μ] for imperfect resolution are generally satisfactory. Choosing the appropriate instrumental spreading function is however a very difcult task. There is need for further research on this problem, in particular with polymer standards for which the DMWD or even Mz is known (in addition to Mn and Mw).A criterion for resolution in GPC which is based on a solution of Tung's axial dispersion equation has been proposed.The operation of GPC in recycle mode appears very promising. Equations have been developed to interpret data obtained in this operational mode. It is probable that a great deal of work will be done in this area in the very near future.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 1607-1622 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Numerical methods for the solution of Tung's axial dispersion equation have been developed and comprehensively evaluated. These methods are general and can be applied where the instrumental spreading function is unsymmetrical and nonuniform. Computation times required are comparable to those of the method of Chang and Huang being about 10 sec per case on the CDC6400 computer. Memory requirements are minimal and this should permit their use with minicomputers for data acquisition and processing.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 783-799 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The bulk polymerization of vinyl chloride initiated by AIBN at temperature levels of 30°, 50°, and 70°C has been studied. Molecular weight averages and distribution (MWD) were measured by gel permeation chromatography. A model has been proposed which accurately predicts conversion to high levels and MWD. Molecular weight measurements show that transfer to monomer plays the important role in controlling molecular weight averages. Disproportionation is probably the dominant mode of termination.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 1093-1101 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: A novel experimental technique based on gel permeation chromatography (GPC) has been developed for the measurement of molecular aggregation in poly(vinyl chloride) (PVC). PVC having a range of syndiotacticity was synthesized using polymerization temperatures of 30-70°C. Tacticity and molecular aggregation of these PVC samples were measured by NMR and GPC, respectively. The temperature dependence of molecular aggregation was found to be much greater than that of tacticity. This GPC technique is inherently more sensitive than NMR in the temperature range normally employed for commercial production of PVC. It should find extensive use in the control of PVC reactors and in PVC processing.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 905-949 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: This manuscript reports on an experimental investigation of the chemical-initiated (AIBN) bulk polymerization of methyl methacrylate to limiting conversion at temperatures of 50°C, 70°, and 90°C. The change in the cumulative differential molecular weight distribution (CDMWD) with respect to conversion was measured by gel permeation chromatography (GPC). These CDMWD's were differentiated to determine the instantaneous differential molecular weight distribution (instantaneous DMWD) over the range of conversions investigated. These experimental instantaneous DMWD's were found to agree with theoretical distributions predicted by classical free-radical kinetics over the entire conversion range and where diffusion control of the termination reactions is dramatic. A correlation of the dimensionless group α (where α = ktdRp/kp2M2) with free volume is proposed. This correlation appears to adequately account for diffusion control of the termination reaction. A kinetic model for the bulk polymerization of methyl methacrylate has been developed. This model should find use in the design, simulation, and optimization of PMMA reactors.
    Zusätzliches Material: 19 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 3769-3778 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: This manuscript reports an experimental investigation of the mechanical degradation of polyacrylamide in aqueous solution using a high-shear couette viscometer. Equilibrium molecular weight distributions (MWD) at various shear stresses were measured by gel permeation chromatography. Degradation data indicate that the MWD becomes narrower at higher shear stresses, in general agreement with Bueche's midpoint break theory. An empirical correlation of the critical molecular weight and degrading shear stress is presented. It has the form \documentclass{article}\pagestyle{empty}\begin{document}$ M_C = \frac{{3.59 \times 10^8 }}{{\tau ^{0.41} }} $\end{document} where Mc is the critical molecular weight and τ is the degrading shear stress in dynes/cm2.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 1603-1609 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The applicability of a model after Talamini for the bulk polymerization of vinyl chloride with several commercial initiators has been examined. The model agrees well with experimental rate data for the initiators: diisopropyl peroxydicarbonate, disecbutyl peroxydicarbonate, t-butyl peroxypivalate, lauroyl peroxide and benzoyl peroxide.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 1431-1442 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: This manuscript reports on the development of a high-shear Couette viscometer. The main design considerations for a high-shear concentric cylinder viscometer are reviewed and discussed. In principle, the instrument is identical to those used by other investigators. However, some modifications were found necessary. Attention is drawn to the importance of the concentricity problem. The instrument was first tested and calibrated using Newtonian standard oils. Then non-Newtonian runs were performed using narrow polystyrene standards of molecular weights 97,200, 411,000, and 860,000. Solutions of the polymer in n-butylbenzene ranged in concentration from 0.08 g/cc up to 0.5 g/cc. The shear rates applied ranged from 103 sec-1 up to 105 sec-1. The results obtained were compared to the molecular entanglement theory, and excellent agreement was observed.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 1479-1506 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The solution polymerization of acrylamide initiated by 4,4′-azobis-4-cyanovaleric acid (ACV) at high monomer concentrations in the temperature range 25-50°C has been studied. Molecular weight distributions were measured by gel permeation chromatography and by electron microscopy. Molecular weight measurements show that transfer to monomer plays a dominant role in controlling the molecular weight averages.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...