Cryoscopic and Viscosity Studies of Polyisobutylene. Cryoscopic Deviation of Polyisobutylene Solutions from Raoult's Law

1943 ◽  
Vol 16 (1) ◽  
pp. 69-84
Author(s):  
A. R. Kemp ◽  
H. Peters
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Infinite Dilution ◽  
Freezing Point ◽  
Raoult’S Law ◽  
Ideal Solutions ◽  
Chain Lengths ◽  
Selection Of ◽  
Raoult's Law

Abstract 1. The cryoscopic method is not satisfactory for polyisobutylenes having chain lengths much over 40 isobutylene units, on account of the failure of their solutions to obey Raoult's law. 2. The present work has led to the selection of a Kcm value of 0.75×104 for n-hexane solutions of polyisobutylene for use in the equation M=(log ηr×Kcm)/C. 3. Extrapolation of cryoscopic data obtained on nonideal solutions to infinite dilution gives inordinately high molecular weight values compared with those based on freezing point measurements of ideal solutions. 4. Of several solvents studied, n-hexane was found to be the best for viscosity—molecular weight measurements of polyisobutylene. 5. Fractionation of polyisobutylene by diffusion into mixtures of n-hexane and acetone resulted in the separation of the lower polymer fractions.

Viscosity-Molecular Weight of Rubber. Cryoscopic Deviation of Rubber Solutions from Raoult's Law

1942 ◽  
Vol 15 (1) ◽  
pp. 60-71
Author(s):  
A. R. Kemp ◽  
H. Peters
Keyword(s):  
Molecular Weight ◽  
Large Deviations ◽  
Raoult’S Law ◽  
Chain Lengths ◽  
Selection Of ◽  
Raoult's Law

Abstract 1. The cryoscopic method is not satisfactory for polyprenes with chain lengths much greater than about 20 isoprene units on account of the failure of their solutions to obey Raoult's law. 2. Since Staudinger's viscosity-molecular weight constants were in many cases determined on nonideal solutions, this subject will be further investigated. 3. The present work has led to the selection of a Kcm value of 0.75 × 104, which is 25 per cent lower that the value chosen by Staudinger, who used higher polymers which do not behave ideally in solution. 4. The use of Staudinger's equation, M=ηsp/CKm, leads to large deviations with the variations in viscosity usually employed, and this deviation is largely avoided by employing the equation M=(log ηr/C)Kcm.

Viscosity and Cryoscopic Data on Polystyrene. Discussion of Staudinger's Viscosity Rule

1943 ◽  
Vol 16 (1) ◽  
pp. 58-68
Author(s):  
A. R. Kemp ◽  
H. Peters
Keyword(s):  
Molecular Weight ◽  
Raoult’S Law ◽  
Wide Range ◽  
Raoult's Law

Abstract 1. The cryoscopic method is not satisfactory for polystyrenes containing more than twelve styrene units in the chain on account of the failure of their solutions to obey Raoult's law. 2. The present work has established a new Kcm value of 0.45×104 for benzene solutions of polystyrene to be used in the equation: A Kcm value of 0.6×104 has been similarly established for benzene solutions of polyindene. 3. Increased confidence in the viscosity-molecular weight procedure is derived from the data presented for the new Kcm equivalent covering a wide range of different polymers.

Determination of Isosmolar Blood Anticoagulant Solutions by the Freezing-Point Method

1958 ◽  
Vol 4 (2) ◽  
pp. 142-145 ◽  
Author(s):  
Harold M Kaplan ◽  
Edward F Stephens
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Freezing Point ◽  
Point Method

Abstract Freezing-point depressions of several anticoagulants were determined from which concentrations isosmolar with the blood of any species may be computed. The method is not applicable to solutes of high molecular weight.

The composition of grape cuticle wax

1965 ◽  
Vol 18 (7) ◽  
pp. 1059 ◽  
Author(s):  
F Radler ◽  
DHS Horn
Keyword(s):  
Fatty Acids ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Oleanolic Acid ◽  
Light Petroleum ◽  
Oxidation Products ◽  
Straight Chain ◽  
Neutral Alumina ◽  
Chain Lengths ◽  
Long Chain

The cuticle wax of the grape is composed of a soft wax (30%) readily removed by light petroleum and a hard wax (30%), mainly oleanolic acid, removed by chloroform. The soft wax of the fresh grape is composed chiefly of long-chain alcohols together with smaller amounts of aldehydes, esters, fatty acids, hydrocarbons, oleanolic acid, and small amounts of high molecular weight substances. The soft wax of dried grapes is similar in composition but contains no aldehydes and larger amounts of high molecular weight substances and oxidation products. The aldehydes, unusual wax components, are straight chain and range from C16 to C32 with the even chain-lengths predominating. They were destroyed by neutral alumina but can be chromatographed on silicic acid.

Infinite-Dilution Viscoelastic Properties of Polystyrene of Very High Molecular Weight

1978 ◽  
Vol 11 (5) ◽  
pp. 1060-1062 ◽  
Author(s):  
Robin W. Rosser ◽  
John L. Schrag ◽  
John D. Ferry
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Viscoelastic Properties ◽  
Infinite Dilution ◽  
Very High

Selection of a Mutant Strain Streptococcus equi SH-109 and Optimization of Culture Conditions for the Production of High Molecular Weight Hyaluronic Acid

2014 ◽  
Vol 915-916 ◽  
pp. 909-912 ◽  
Author(s):  
Jian Cheng Feng ◽  
Rong Hu Zhang
Keyword(s):  
Molecular Weight ◽  
Hyaluronic Acid ◽  
High Molecular Weight ◽  
Culture Conditions ◽  
Culture Broth ◽  
Agitation Speed ◽  
Wild Type ◽  
Streptococcus Equi ◽  
Optimal Ph ◽  
Selection Of

A high molecular weight hyaluronic acid-producing mutant, designated asStreptococcus equiSH-109 that did not produce streptolysin or hyaluronidase was selected from wild-typeStreptococcus equiSH-0 by NTG treatment. The selected mutant could produce high molecular weight HA and had perfect genetic stability after reproduction. Several culture conditions were optimized in a 5-l fermentor for the production of hyaluronic acid. It was found that the optimal pH and agitation speed were 7.6 and 550rpm, respectively. Under the optimized culture condition, hyaluronic acid with a molecular weight of 4.0 x 106was accumulated in the culture broth.

SOME PROPERTIES OF PURE POLYOXYETHYLENEGLYGOL ETHERS IN SOLUTION

1961 ◽  
Vol 39 (2) ◽  
pp. 331-338 ◽  
Author(s):  
A. F. Sirianni ◽  
B. A. Gingras
Keyword(s):  
Critical Micelle Concentration ◽  
Infinite Dilution ◽  
Solution Properties ◽  
Raoult’S Law ◽  
Association Patterns ◽  
Solvation Effects ◽  
Molecular Weights ◽  
Hydrophobic Portion ◽  
Apparent Association ◽  
Raoult's Law

Solution properties of a series of hexaoxyethyleneglycol ethers having 8 to 16 carbon atoms in a paraffin chain along with a number of diethers were assessed in ethanol at 48 and 60 °C. The molecular weights at infinite dilution indicated that the compounds are unassociated. Solvation effects were observed for the monoethers having 14 or more carbon atoms in the hydrophobic portion of the molecule, but were absent for those molecules containing 12 carbon atoms or less. The apparent micellar weights suggested that association did not proceed beyond a dimer for most of the hexaoxyethyleneglycol compounds. The diethers obeyed Raoult's law up to the critical micelle concentration while different apparent association patterns were observed beyond this concentration.

THE SYSTEM NAPHTHALENE–p-NITROPHENOL: AN EXPERIMENTAL INVESTIGATION OF ALL THE VARIABLES IN AN EQUATION OF THE FREEZING POINT CURVE

1941 ◽  
Vol 19b (3) ◽  
pp. 73-85 ◽  
Author(s):  
A. N. Campbell ◽  
A. J. R. Campbell
Keyword(s):  
Surface Tension ◽  
Freezing Point ◽  
Heat Of Fusion ◽  
Heat Of Mixing ◽  
Raoult’S Law ◽  
Compound Formation ◽  
Point Curve ◽  
Freezing Curve ◽  
The Ideal ◽  
Raoult's Law

With the object of determining the factors responsible for the inapplicability of the ideal equation of the freezing curve,[Formula: see text]a number of experimental determinations have been carried out on the system naphthalene–p-nitrophenol. These were: (i) specific heat, (ii) heat of fusion, (iii) heat of mixing, (iv) vapour pressure, (v) vapour composition, (vi) density, (vii) surface tension, (viii) viscosity.The conclusion is arrived at that the discrepancy is due principally to the invalidity of Raoult's law in this case. Since the deviation is positive with respect to both components, it cannot be ascribed to compound formation in solution. Apart from the deviation from Raoult's law, the solution does not exhibit marked abnormality.The data obtained also permit of the complete, or almost complete, construction of the p–t–x model for this system.

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