Micellar Molecular Weights of Some Paraffin Chain Salts by Light Scattering

1955 ◽  
Vol 59 (12) ◽  
pp. 1185-1190 ◽  
Author(s):  
H. V. Tartar ◽  
A. L. M. Lelong
Keyword(s):  
Light Scattering ◽  
Molecular Weights

Preparation of graft copolymers by the reaction of polymeric acyl chlorides with monohydroxy-terminated polymers: An introductory study

1988 ◽  
Vol 53 (8) ◽  
pp. 1735-1744 ◽  
Author(s):  
Jitka Horská ◽  
Jaroslav Stejskal ◽  
Pavel Kratochvíl ◽  
Aubrey D. Jenkins ◽  
Eugenia Tsartolia ◽  
...  
Keyword(s):  
Light Scattering ◽  
Chemical Composition ◽  
Statistical Model ◽  
Graft Copolymers ◽  
Coupling Reaction ◽  
Molecular Characteristics ◽  
Gel Formation ◽  
Acyl Chlorides ◽  
Molecular Weights

An attempt was made to prepare well-defined graft copolymers by the coupling reaction between acyl chloride groups located along the backbone chain and monohydroxy-terminated grafts prepared separately. The molecular weights and the parameters of heterogeneity in chemical composition of the products were determined by light scattering and osmometry. The determination of molecular characteristics revealed that the degree of grafting was low. The results therefore could not be confronted with a statistical model at this stage. The problems encountered in the synthesis, e.g., gel formation, and the data relating to the soluble products are discussed.

FRACTIONATION OF LIVETIN AND THE MOLECULAR WEIGHTS OF THE α- AND β-COMPONENTS

1957 ◽  
Vol 35 (4) ◽  
pp. 241-250 ◽  
Author(s):  
W. G. Martin ◽  
J. E. Vandegaer ◽  
W. H. Cook
Keyword(s):  
Light Scattering ◽  
Soluble Protein ◽  
Soluble Fraction ◽  
Egg Yolk ◽  
Water Soluble ◽  
Water Soluble Fraction ◽  
Molecular Weights ◽  
Water Soluble Protein ◽  
Hen Egg Yolk ◽  
Hen Egg

Livetin, the major water-soluble protein of hen egg yolk, was found to contain three major components having mobilities of −6.3, −3.8, and −2.1 cm.2 sec.−1 volt−1 at pH 8, µ 0.1, and these have been designated α-, β-, and γ-livetin respectively. The α- and β-livetins were separated and purified electrophoretically after removal of γ-livetin by precipitation from 37% saturated ammonium sulphate or 20% isopropanol. The α-, β-, and mixed livetins resembled pseudoglobulins in solubility but γ-livetin was unstable and this loss of solubility has, so far, prevented its characterization. Molecular weights determined by light scattering, osmotic pressure, and Archibald sedimentation procedure yielded respectively: 8.7, 7.8, and 6.7 × 104 for α-livetin, and 4.8, 5.0, and4.5 × 104 for β-livetin. Under suitable conditions of sedimentation and electrophoresis, egg yolk has been shown to contain three components having the same behavior as the three livetins of the water-soluble fraction.

Structure of Polybutadienes

1967 ◽  
Vol 40 (5) ◽  
pp. 1529-1543 ◽  
Author(s):  
W. S. Bahary ◽  
D. I. Sapper
Keyword(s):  
Light Scattering ◽  
Molecular Size ◽  
Structural Features ◽  
Melting Point Depression ◽  
Linear Polymers ◽  
Long Chain Branching ◽  
Molecular Weights ◽  
Catalyst Systems ◽  
Molecular Size Distribution

Abstract Polybutadienes made with six different catalyst systems were examined: (1) butyllithium, (2) “nickel-based”, (3) alfin, (4) “titanium-based”, (5) “cobalt-based”, and (6) free radical emulsion. The microstructure and macrostructure of the polybutadienes have been determined and are compared to the results published in the literature. These polybutadienes may be considered to be random terpolymers of cis, trans, and vinyl addition of butadiene. The glass transition temperature is specified by the vinyl content. The crystalline melting points of the high trans and also the high cis polybutadienes obey to a high measure Flory's equation for melting point depression of a random terpolymer. The molecular weights of the polybutadienes have been determined by light scattering and osmometry and the degree of long chain branching has been determined by the branching index, 〈g′〉. The macro-structural features of the linear polymers are confirmed by fractionation. However, the polydispersities calculated from fractionation data do not agree with those determined from light scattering and osmometry for the branched samples. The discrepancy is attributed to the method of characterization of the fractions. A distinction is made between molecular weight distribution and molecular size distribution.

Evaluation of polydispersity index Mw/Mn by quasielastic light scattering

1987 ◽  
Vol 52 (5) ◽  
pp. 1235-1245 ◽  
Author(s):  
Petr Štěpánek ◽  
Zdeněk Tuzar ◽  
Čestmír Koňák
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Decay Time ◽  
Sampling Time ◽  
Polydispersity Index ◽  
New Method ◽  
Molecular Weights ◽  
Quasielastic Light Scattering ◽  
Good Agreement

The response of quasielastic light scattering to the polydispersity of scattering objects has been investigated. A new method of the polydispersity index determination has been suggested, suitable for the range 1.02 ⪬ Mw/Mn ⪬ 2.0 and consisting in the measurement of the dependence of the apparent decay time on the correlator sampling time. The polydispersity index can be determined by comparing these dependences with the theoretical ones obtained using correlation curves simulated for various values of the polydispersity index, assuming lognormal and Schulz-Zimm distributions of molecular weights. The test measurements on polystyrene standards having molecular weights in the range 9 103 – 20.6 106 give polydispersity index values Mw/Mn that are in a good agreement with those given by the manufacturer. The polydispersity index for polystyrene having the molecular weight Mw = 20.6 106 thus determined was Mw/Mn = 1.35.

The Determination of Polymeric Molecular Weights by Light Scattering in Solvent‐Precipitant Systems

1946 ◽  
Vol 14 (11) ◽  
pp. 687-695 ◽  
Author(s):  
R. H. Ewart ◽  
C. P. Roe ◽  
P. Debye ◽  
J. R. McCartney
Keyword(s):  
Light Scattering ◽  
Molecular Weights
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