Determination of number-average molecular weight of atactic polystyrene and cellulose diacetate by vapour pressure osmometry

1983 ◽  
Vol 15 (2) ◽  
pp. 91-94 ◽  
Author(s):  
Kenji Kamide ◽  
Toshikazu Terakawa ◽  
Shigenobu Matsuda
Keyword(s):  
Molecular Weight ◽  
Vapour Pressure ◽  
Average Molecular Weight ◽  
Number Average Molecular Weight ◽  
Cellulose Diacetate ◽  
Atactic Polystyrene

EBULLIOMETRY AND THE DETERMINATION OF THE MOLECULAR WEIGHTS OF POLYMERS: PART I. THE SMALL EBULLIOMETER

1959 ◽  
Vol 37 (9) ◽  
pp. 1508-1516 ◽  
Author(s):  
W. R. Blackmore
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Number Average Molecular Weight ◽  
Molecular Weights

An ebulliometer that has been in routine use for the determination of the number average molecular weight of polymers is described. The results obtained with two different series of polythenes (which were also measured elsewhere) are given. These results show this ebulliometer to be subject to experimental difficulties which limit it to number average molecular weights of perhaps 20,000 depending on the precision required.

Synthesis and characterization of poly(coumarin-urethane)s

1994 ◽  
Vol 6 (3) ◽  
pp. 257-262
Author(s):  
D I Brahmbbatt ◽  
L Jayabalan ◽  
Harshad D Patel
Keyword(s):  
Molecular Weight ◽  
Elemental Analysis ◽  
Vapour Pressure ◽  
Condensation Reaction ◽  
Average Molecular Weight ◽  
Spectral Studies ◽  
Synthesis And Characterization ◽  
Molecular Weight Determination ◽  
Number Average Molecular Weight

Poly(coumarin-urethane)s (PCUs) were prepared by the condensation reaction of 3,3'-dihydroxy-6,6'-methylcnebiscoumarin (DHMBC) with various diisocyanates. All the poly(coumarin-urethane)s were characterized by elemental analysis, IR spectral studies, number average molecular weight determination (by vapour pressure osmometry), viscosity studies and thermogravimetry.

scholarly journals A determination of the sub-units of arachin by osmometry. Arachins A, B and A1

1967 ◽  
Vol 105 (1) ◽  
pp. 181-187 ◽  
Author(s):  
M. P. Tombs ◽  
M. Lowe
Keyword(s):  
Molecular Weight ◽  
Osmotic Pressure ◽  
Gel Electrophoresis ◽  
Average Molecular Weight ◽  
Urea Concentration ◽  
Suitable Method ◽  
Number Average Molecular Weight ◽  
Disulphide Bonds ◽  
New Form

1. Osmotic pressure determinations of dissociated arachins are a particularly suitable method for determination of the number of sub-units in the protein, because they yield a number-average molecular weight. 2. Arachin, in 8m-urea–0·1m-sulphite, produces 12 sub-units from the form of molecular weight 345000. 3. When the urea concentration is varied the molecules became fully dissociated at 6m-urea–0·1m-sulphite. Although sulphite is necessary to break disulphide bridges, concentrations greater than 0·1m cause a re-aggregation of the sub-units. Similar results were obtained in guanidine solutions. 4. A new form of arachin has been discovered, A1, migrating more rapidly than arachin A. 5. The N-terminal residues of arachin have been re-investigated on more highly purified samples: they are glycine, valine and (iso)leucine in the proportions 4:1:1. 6. The three forms of arachin have the structure (B) β4γδ, (A) α2β2γδ and (A1) α4γδ, for the forms of molecular weight 170000. 7. Dissociation in 8m-urea produces some fragments, detected by gel electrophoresis, which appear to be dimers of the type α-S-S-β, β-S-S-β, held together by disulphide bonds.

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