Number- and Weight-Average Molecular Weights for Some Proanthocyanidin Polymers (Condensed Tannins)

1986 ◽  
Vol 39 (4) ◽  
pp. 557 ◽  
Author(s):  
LJ Porter
Keyword(s):  
Condensed Tannins ◽  
Laser Light ◽  
Gel Permeation Chromatography ◽  
Laser Light Scattering ◽  
Polymer Chains ◽  
Average Chain Length ◽  
Molecular Weights ◽  
Scattering Measurements ◽  
Gel Permeation ◽  
Derivatives Of

The number-average molecular weights (Mn) and weight-average molecular weights (Mw) for proanthocyanidin polymers (condensed tannins) have been measured by vapour pressure osmometry and low-angle laser light-scattering measurements in methanol. These confirm earlier findings (based on gel permeation chromatography of the peracetate derivatives of these polymers) that they are polydisperse. The results also indicate that the incidence of branching in the polymer chains increases as the average chain length increases.

Synthesis and characterization of novel organosoluble aromatic copolyimides

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Jintian Yang ◽  
Wei Huang ◽  
Yongfeng Zhou ◽  
Deyue Yan ◽  
Xiaohang Wang
Keyword(s):  
Gel Permeation Chromatography ◽  
Polymer Chains ◽  
Polymerization Process ◽  
Synthesis And Characterization ◽  
Aprotic Solvents ◽  
Solution Casting ◽  
Molecular Weights ◽  
Gel Permeation ◽  
Dipolar Aprotic Solvents

AbstractA series of novel aromatic copolyimides was synthesized from pyromellitic dianhydride with the commercial diamine 4,4’-methylenebisaniline (MBA) and the diamine 4,4’-methylenebis(2-tert-butylaniline) (MBTBA) specially designed by ourselves. The solubility of the copolyimides in conventional solvents decreased with the mole ratio of MBTBA to MBA. When MBTBA/MBA was larger than 8/2, the copolyimides are soluble in low boiling point solvents (such as chloroform and tetrahydrofuran) and can form a transparent, flexible, tough film by solution casting. When MBTBA/MBA was between 7/3 and 5/5, the copolyimides are only soluble in dipolar aprotic solvents (such as dimethylformamide and N-methyl-2-pyrrolidone) and form films, too. The copolyimide was precipitated in m-cresol in the polymerization process when MBTBA/MBA was lower than 5/5. The number-average molecular weights of the soluble copolyimides measured by gel permeation chromatography were larger than 5.0·104 and the polydispersity index was higher than 1.5. Only one glass transition of these copolyimides was detected at around 350°C. The copolyimides did not show appreciable decomposition up to 400°C under air and 550°C under nitrogen, and their thermal stability increased a little with the introduction of MBA into the polymer chains.

Detection of serum proteins by high-pressure gel-permeation chromatography with low-angle laser light scattering, compared with analytical ultracentrifugation.

1986 ◽  
Vol 32 (2) ◽  
pp. 363-367 ◽  
Author(s):  
W Flapper ◽  
P J van den Oetelaar ◽  
C P Breed ◽  
J Steenbergen ◽  
H J Hoenders
Keyword(s):  
High Pressure ◽  
Light Scattering ◽  
Analytical Ultracentrifugation ◽  
Laser Light ◽  
Serum Proteins ◽  
Gel Permeation Chromatography ◽  
Laser Light Scattering ◽  
Gel Permeation ◽  
Human Sera ◽  
Molecular Masses

Abstract Human sera were subjected to analytical ultracentrifugation and "high-pressure" gel-permeation chromatography on a system of combined TSK Gel G5000 PW and G3000 SW columns. The chromatographic method produced remarkably superior resolution of the proteins, especially those exceeding 100 000 Da. We calculated the molecular masses of eluted fractions on the basis of their detection by low-angle laser light scattering and their differential refractive index. We discuss the results in relation to the clinical data.

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