The viscosity of an exocellular polysaccharide (EPS) produced by the bacterium Lactococcus lactis subsp. cremoris B40 was studied in aqueous solution at an ionic strength of 0.10M. First, the zero-shear viscosity was determined as a function of the concentration. From the data in the low concentrati
Concentration dependence on viscosity of oligourethane diols
โ Scribed by Syed Haseebuddin; K. V. S. N. Raju; M. Yaseen
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 145 KB
- Volume
- 66
- Category
- Article
- ISSN
- 0021-8995
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โฆ Synopsis
To obtain viscosity suitable for application, relatively low molecular weight polymers, i.e., oligomers, are used in the formulation of high solids coatings. To support this requirement, the concentration dependence of the viscosity of synthesized oligourethane diols in different solvents was analyzed using Erickson's models. By regression analysis, it was found that the correlation coefficients are fairly good and the plots of the residuals are more random. The weight intrinsic viscosity, [h w ], composed of the oligomer component, O [ h]w , and the oligomer-solvent interaction component, I [ h]w , was calculated from the intercept of the plot of 1/ln h r vs. 1/w 0 . The parameter I [ h]w , related to the solvent molar volume and the distance between the oligomer and solvent partial cohesion parameter coordinates, indicates the degree of interaction between the oligomer and solvent. The partial cohesion parameters of the oligomers obtained by the group-contribution method were used for calculating the interaction component of oligourethane diols.
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