scholarly journals Hydrodynamic Properties of Gelatin - Studies from Intrinsic Viscosity Measurements

10.5772/34401 ◽  
2012 ◽  
Author(s):  
Martin Alberto ◽  
Maria Gabriela
Keyword(s):  
Intrinsic Viscosity ◽  
Hydrodynamic Properties ◽  
Viscosity Measurements

MOLECULAR WEIGHT AND HYDRODYNAMIC PROPERTIES OF SODIUM ALGINATE

1954 ◽  
Vol 32 (3) ◽  
pp. 227-239 ◽  
Author(s):  
W. H. Cook ◽  
David B. Smith
Keyword(s):  
Molecular Weight ◽  
Sodium Alginate ◽  
Intrinsic Viscosity ◽  
Diffusion Coefficients ◽  
Linear Relation ◽  
Hydrodynamic Properties ◽  
Viscosity Measurements ◽  
Molecular Weights ◽  
Extension Ratio ◽  
Good Agreement

Sedimentation, diffusion, and viscosity measurements were made on five unfractionated samples of sodium alginate ranging in intrinsic viscosity from 3.1 to 17.5. Diffusion coefficients were subject to large errors and are believed to be overestimated.Though the molecular weights obtained from sedimentation–diffusion (Svedberg equation) and sedimentation – intrinsic viscosity (Perrin–Simha equations) showed good agreement and yielded values of 3 to 21 × 104, higher values (4.6 to 37 × 104) from sedimentation–viscosity (Mandelkern–Flory equation) appear to be the better estimates. A linear relation between intrinsic viscosity and molecular weight was found with a slope (Mandelkern–Flory equation values) equivalent to Km = 13.9 × 10−3. The results indicate that sodium alginate has a relatively high extension ratio.

MOLECULAR WEIGHT AND HYDRODYNAMIC PROPERTIES OF SODIUM ALGINATE

1954 ◽  
Vol 32 (1) ◽  
pp. 227-239 ◽  
Author(s):  
W. H. Cook ◽  
David B. Smith
Keyword(s):  
Molecular Weight ◽  
Sodium Alginate ◽  
Intrinsic Viscosity ◽  
Diffusion Coefficients ◽  
Linear Relation ◽  
Hydrodynamic Properties ◽  
Viscosity Measurements ◽  
Molecular Weights ◽  
Extension Ratio ◽  
Good Agreement

Sedimentation, diffusion, and viscosity measurements were made on five unfractionated samples of sodium alginate ranging in intrinsic viscosity from 3.1 to 17.5. Diffusion coefficients were subject to large errors and are believed to be overestimated.Though the molecular weights obtained from sedimentation–diffusion (Svedberg equation) and sedimentation – intrinsic viscosity (Perrin–Simha equations) showed good agreement and yielded values of 3 to 21 × 104, higher values (4.6 to 37 × 104) from sedimentation–viscosity (Mandelkern–Flory equation) appear to be the better estimates. A linear relation between intrinsic viscosity and molecular weight was found with a slope (Mandelkern–Flory equation values) equivalent to Km = 13.9 × 10−3. The results indicate that sodium alginate has a relatively high extension ratio.

Copolymerization of ethylene and 4-vinylcyclohexene by various metallocenes in the presence of Al(iBu)3/[Ph3C][B(C6F5)4]

e-Polymers ◽  
2001 ◽  
Vol 1 (1) ◽  
Author(s):  
Il Kim ◽  
Young-tae Kim
Keyword(s):  
Double Bond ◽  
Intrinsic Viscosity ◽  
Polymerization Rate ◽  
Viscosity Measurements

AbstractCopolymerizations of ethylene and 4-vinylcyclohexene (VCH) were carried out with isospecific rac-1,2-ethylenebis(1-indenyl)Zr(N(CH3)2)2 [rac-(EBI)Zr(NMe2)2] and syndiospecific isopropylidene(cyclopentadienyl)(9- fluorenyl)ZrMe2 [iPr(Cp)(Flu)ZrMe2] compounds combined with Al(iBu)3/ [Ph3C][B(C6F5)4] as a cocatalyst system. VCH was regioselectively inserted into the copolymer through the vinyl double bond, leaving the endocyclic double bond unreacted. rac-(EBI)Zr(NMe2)2 catalyst showed a higher polymerization rate but lower VCH reactivity than the iPr(Cp)(Flu)ZrMe2 catalyst. The calculation of copolymerization parameters according to Kelen-Tüdös resulted in rE = 131.49 and rVCH = 0.02 for the iPr(Cp)(Flu)ZrMe2 catalyst. When [VCH] in feed was 90.5 mol-%, [VCH] in polymer was 1.88 and 8.04 mol-% for rac-(EBI)Zr(NMe2)2 and iPr(Cp)(Flu)ZrMe2 catalysts, respectively. The resulting copolymers were characterized using NMR, Raman and intrinsic viscosity measurements.

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