Viscosity of solution

Before we are in a position to discuss the viscosity of polymer melts, we must first give a quantitative definition of what is meant by viscosity and then say something about how this property is measured. This will not be our only exposure to experimental viscosity in this volume—other methods for determining bulk viscosity will be taken up in the next chapter and the viscosity of solutions will be discussed in Chap. 9—so the discussion of viscometry will only be introductory. Throughout we shall be concerned with constant temperature experiments conducted under nonturbulent flow conditions. 

With this terminology in mind, we can restate the objective of this section as the interpretation of the intrinsic viscosities of solutions of rigid molecules. If the solute molecules are known to be spherical, comparison of Eqs. (9.10) and (9.14) shows that the intrinsic viscosity for such systems is given by... 

Locust bean gum is not completely soluble in cold water it must be heated to 80°C and cooled to attain a stable solution that has high viscosity at low concentrations. The gum is compatible with other plant gums and the viscosity of solutions is not appreciably affected by pH or salts. 

The viscosity of solutions is quite temperature dependent increasing the temperature leads to a reduction in viscosity, which approaches zero at approximately 60°C (322). The viscosity is relatively stable from pH 3—10 and is compatible with a number of inorganic salts other than sodium. The production of succinoglycan and its potential use in foods and industrial processes as a thickening agent has been described (322). 

Complete recovery possible in theory (in practice, recovery dictated by solubiUty limit of impurities and viscosity of solution). 

This polymer may be prepared by stirring the molten w-aminoundecanoic acid at about 220°C. The reaction may be followed by measurements of the electrical conductivity of the melt and the intrinsic viscosity of solutions in w-cresol. During condensation 0.4-0.6% of a 12-membered ring lactam may be formed by intramolecular condensation but this is not normally removed since its presence has little effect on the properties of the polymer. 

Fig. 2.52 Kinematic viscosity of solution vs. temperature at various Habon G concentrations. Circles (O) indicate water Habon G, boxes ( ) represent 130ppm, crosses (x) represent 260ppm, empty triangles (A) represent 530 ppm, triangles (A) represent 1,060 ppm. Reprinted from Hetsroni et al. (2001b) with permission...

Simha, R. The Influence of Brownian Movement on the Viscosity of Solutions. J. Phys. Chem. 44, (1940) 25-34. 

Figure 9. Change with time of viscosity of solutions of hydrolyzed poly(starch g (2 propenamide)) copolymer.

When we compared the viscosities of solutions of natural rubber and of guttapercha and of other elastomers and later of polyethylene vs.(poly)cis-butadiene, with such bulk properties as moduli, densities, X-ray structures, and adhesiveness, we were greatly helped in understanding these behavioral differences by the studies of Wood (6) on the temperature and stress dependent, melting and freezing,hysteresis of natural rubber, and by the work of Treloar (7) and of Flory (8) on the elasticity and crystallinity of elastomers on stretching. Molecular symmetry and stiffness among closely similar chemical structures, as they affect the enthalpy, the entropy, and phase transitions (perhaps best expressed by AHm and by Clapeyron s... 

Vand, V. J. Phys. Coll. Chem. 52 (1948) 277. Viscosity of solutions and suspensions. 

Viscosity is a measure of the resistance to flow of a material, mixture, or solution. Here we will consider the viscosity of solutions containing small, generally 1 g/100 cc (called 1% solutions) and less, amounts of polymer. The study of such dilute polymer solutions allows a determination of a relative molecular weight. The molecular weight is referred to as relative since... 

Figure 4.5. Dependence of pol5nnerization rate of MA (1) and specific viscosity of solutions of equimolar mixtures of polyacid and PEG (2) on molecular weight of PEG. 1 -[MA]=[PEG]=3.5x10 2 [K2S2O8]=3.7x10 mol/L, 50 C. 2 - PMA M=170,000 cpma=0.1 g/dL, 45 C. Reprinted from I. M. Papisov, V. A. Kabanov, E. Osada, M. Leskano Brito, J. Reimont, and A. N. Gvozdeckii, Vysokomol. Soed., 14, 2462 (1972) with kind permission from Iz. Nauka.

The viscosity of solutions of polymers is inversely related to the temperature. The viscosity may be approximated by the Arrhenius equation at temperatures up to 100 K above the Tt and is more dearly expressed by the Arrhenius equation at higher temperatures ... 

Fig. 19. Relationship between ethanol content, rate constant (ft), and viscosity of solution in the electron-m transfer reaction for poly(N-vinyl-3 2-methylimidazole)-Co(III) Fe-edta2 87 ...

The relative viscosity of solutions of cellulose nitrate in acetone was measured and extrapolated to zero rate of shear ... 

The reaction between 3,5-diaminoanisole and acid dianhydrides in amide solvents (above all N-methyl-2-pyrrolidone, NMP) was conducted at room temperature. The process occurred in a homogeneous system and led to PCA with relatively high, reduced viscosities of solution (Table 5.1). 

Dreval.V.Ye., Tager,A.A., Fomina,A.S. Concentrated solutions of polymers. IV. Viscosity of solutions of polystyrene in various solvents. Polymer Sci. USSR 5,495-507 (1964) [Vysokomolekul. Soyedin. 5,1404 (1963). 

Effect of storage on viscosity. Factors such as the method of storing undissolved nitrocellulose affect the viscosity of its solutions. It has been established (Kanamaru [73]) that nitrocellulose kept in a polar liquid, e.g. water, alcohol, and tested for viscosity at stated periods by dissolving samples in acetone, shows for the first few days a rather rapid increase in viscosity, which gradually becomes slower. If cellulose is stored in a non-polar liquid, such as carbon tetrachloride, or petroleum ether, then the viscosity of solutions remains unchanged or increases only very slightly. 

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