Results 211 to 220 of about 765,777 (264)
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Journal of Applied Polymer Science, 2006
AbstractThe influence of the polymerization time on the molecular weight (Mw, Mn, Mp, and Mz), molecular weight distribution (MWD) and relative MWD of polypropylene (PP) in the propylene polymerization with a Mg(OEt)2/DIBP/TiCl4/PTES/AlEt3 catalyst system in the slurry phase has been studied by using gel permeation chromatography (GPC), where Mg(OEt)2,
Abedi, S. +3 more
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AbstractThe influence of the polymerization time on the molecular weight (Mw, Mn, Mp, and Mz), molecular weight distribution (MWD) and relative MWD of polypropylene (PP) in the propylene polymerization with a Mg(OEt)2/DIBP/TiCl4/PTES/AlEt3 catalyst system in the slurry phase has been studied by using gel permeation chromatography (GPC), where Mg(OEt)2,
Abedi, S. +3 more
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Molecular Weight and Molecular Weight Distribution of Kraft Lignins
MRS Proceedings, 1990ABSTRACTKraft lignins are the lignin degradation products from kraft pulping. They are complex, heterogeneous polymers with some polar character. The molecular weight of kraft lignins greatly affect the physical properties of black liquors, and are of primary importance in separation from black liquor and in evaluating potential uses.Several purified ...
Wolfgang Schmidl +2 more
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Molecular Weights and Molecular-Weight Distributions
1977In synthesizing macromolecules in vitro and in vivo, monodisperse macromolecules (i.e., those in which every molecule has the same molecular weight) only occur under specific mechanistic conditions. The overwhelming majority of reactions proceed more or less randomly, and the resulting macromolecular substance shows a more or less broad molecular ...
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Macromolecular Theory and Simulations, 1994
AbstractThe molecular weight distribution (MWD), formed during random crosslinking of polymers whose initial molecular weight distribution is given by the Schulz‐Zimm distribution, is proposed. The obtained equation can be considered as a good approximation even for nonrandom crosslinking reactions such as free‐radical and living crosslinking ...
Hidetaka Tobita +2 more
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AbstractThe molecular weight distribution (MWD), formed during random crosslinking of polymers whose initial molecular weight distribution is given by the Schulz‐Zimm distribution, is proposed. The obtained equation can be considered as a good approximation even for nonrandom crosslinking reactions such as free‐radical and living crosslinking ...
Hidetaka Tobita +2 more
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Distribution of molecular weights of pectin propionates
Journal of Colloid Science, 1948Abstract A number of pectins have been esterified to form the corresponding propionates. These compounds are readily fractionated according to molecular weights by formation of a saturated solution in a suitable solvent system at a high temperature followed by reduction of the temperature and repetition of the operation several times.
H S, OWENS, J C, MIERS, W D, MACLAY
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Molecular weights and molecular-weight distributions from ultracentrifugation of nonideal solutions
Biophysical Chemistry, 1976Ultracentrifugation, membrane osmometry and capillary viscometry experiments have been performed on two dextran samples, which have molecular-weight distributions (MWDs) similar to those of dextrans used as blood plasma extenders. The manufacturer reported values of Mn and MW, determined by end group analysis and by light scattering, respectively.
P J, Wan, E T, Adams
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Journal of Polymer Science Part A-2: Polymer Physics, 1968
AbstractA method has been developed for determining the molecular weight distribution of a polymer sample from the sedimentation–diffusion equilibrium data for a solution under pseudo‐ideal conditions. From some theoretical examples it appears that the method works well and that the molecular weight distribution can be determined with a reasonable ...
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AbstractA method has been developed for determining the molecular weight distribution of a polymer sample from the sedimentation–diffusion equilibrium data for a solution under pseudo‐ideal conditions. From some theoretical examples it appears that the method works well and that the molecular weight distribution can be determined with a reasonable ...
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Determination of Molecular Weights and Molecular Weight Distribution of Polyacrylamides
SPE Annual Technical Conference and Exhibition, 1984ABSTRACT A high-performance, size-exclusion chromatography procedure has been developed for determining molecular weights and molecular weight distributions of polyacrylamides. The procedure can be applied to dry or emulsion polyacrylamides. Virgin polymers and polymers passed through Berea sandstone cores can be analyzed. The analytical
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Determination of Molecular Weight and Molecular-Weight Distribution
1977Molecular-weight determination methods can be classed as absolute, equivalent, or relative. Absolute methods allow the molecular weight to be calculated directly from the measured quantities; a knowledge of the physical and chemical structure of the molecules is not required.
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Measurement of the Molecular Weight Distribution of Debranched Starch
Biomacromolecules, 2005Combining molecular weight distribution (MWD) data for linear chains of debranched starch from capillary electrophoresis and from size exclusion chromatography (SEC) with detection by differential refractive index and by multi-angle laser light scattering has enabled Mark-Houwink parameters to be determined for linear starch chains.
Castro, J. V. +3 more
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