Reduced viscosity, definition

Some papers60-61 have been devoted to phase separation of polyionic complexes from partially furated (PVA-S) and aminoacetylated (PVA-AAC)poly(vinyl alcohol) in aqueous salt solutions. The separation liquid-liquid or complex coacervation occurs at a definite value of the charge density on the macromolecule. From the concentration dependence of the reduced viscosity of the initial components PVA-S, PVA-AAc and their equivalent mixture in water it follows that the viscosity of the components noticeably increases with dilution, and the curve of the equivalent mixture is concentration independent. This fact confirms the formation of the neutral polymer salt, due to electrostatic interactions of PVA-S (strong polyadd) and PVA-AAc (weak polybase). 

This scaling prediction has been tested against experimental data and appears to be successful for both flexible and semiflexible polymers in good solvents. When plotting a reduced viscosity versus a reduced eoneentration, the best collapse of the data onto a universal curve was found if two different definitions of c were chosen [Raspaudetal., 1995] )]Rouse = = withe = /[ ],andq =... 

In the work [1], the dependences of PHE synthesis main characteristics, namely, reduced viscosity tired and conversion degree Q, on synthesis temperature T were studied. It was found out, that T rising up to the definite limits influences favorably on the indicated process a reaction rate rises, ti and Q increase. This effect can be observed in the narrow enough range of T=333-348 K. At T lower than 333 K PHE formation process decelerates sharply, that is due to insufficient activity of epoxy groups at low temperatures. At T > 353 K cross-linking processes proceed, which are due to the activity enhancement of secondary hydroxyls in polymer chain [1]. It is also supposed [1], that at the indicated temperatures of synthesis PHE branched chains formation is possible. 

Give the definitions and formulas for the relative viscosity, specific viscosity, reduced viscosity, inherent viscosity, and intrinsic viscosity. 

There are mainly two families of epoxies the glycidyl epoxies and non-glycidyl epoxies (also called aliphatic or cycloaliphatic epoxy resins). The absence of aromatic rings in aliphatic epoxies makes them UV resistant and suitable for outdoor applications and also reduces viscosity. The most common epoxy monomers of each family are diglycidylether of bisphenol A (known as DGEBA) and 3,4-Epoxycyclohexyl-3 4 -epoxycyclohexane carboxylate (ECC) respectively and their structures are given in Figure 2 (a, b). Cycloaliphatic resins are usually found in the form of pure chemicals with a definite... 

To understand polymer structure, polymers are often dissolved in appropriate solvents, allowing molecular weight or degree of polymerization to be determined from dilute solution viscosity. The relative viscosity, is the ratio of solution viscosity to that of the solvent. The specific viscosity, is the ratio of the difference in solution and solvent viscosities divided by the solvent viscosity. These dimensionless quantities are often divided by the mass concentration of the polymer to obtain several additional terms that have units of dilution or volume per unit mass concentration the reduced viscosity, which is ratio of the relative viscosity to the concentration the inherent viscosity, which is the ratio of the natural logarithm of the relative viscosity and the intrinsic viscosity, [77], which is the common limiting value of the reduced (Huggins definition) or inherent (Craemer s definition) viscosity at infinite dilution of the polymer. The intrinsic viscosity is a concentration ratio it has been used to estimate molecular... 

It has been shown (16) that a stable foam possesses both a high surface dilatational viscosity and elasticity. In principle, defoamers should reduce these properties. Ideally a spread duplex film, one thick enough to have two definite surfaces enclosing a bulk phase, should eliminate dilatational effects because the surface tension of an iasoluble, one-component layer does not depend on its thickness. This effect has been verified (17). SiUcone antifoams reduce both the surface dilatational elasticity and viscosity of cmde oils as iUustrated ia Table 2 (17). The PDMS materials are Dow Coming Ltd. polydimethylsiloxane fluids, SK 3556 is a Th. Goldschmidt Ltd. siUcone oil, and FC 740 is a 3M Co. Ltd. fluorocarbon profoaming surfactant. 

In Fig. 16 the heat-treated sampie(l) is obtained by heating poly-DSP crystals (a) up to 330°C at a scanning speed of 15°C/min. Then, the sample is cooled immediately to room temperature. The intrinsic viscosity of the original as-polymerized poly-DSP (2.1-2.9) is reduced (0.55-0.59) in sample (1). An X-ray pattern of sample (1) shows slight but definite differences when compared to that erf the original as-polymerized polymer and, in addition, the pattern agrees exactly with that ot the medium-sized polymer crystals (c), which are obtained by photopolymerization of DSP crystals upon irradiation with a xenon lamp for 50 min. DSC curves of sample (1) and polymer crystals (c) are also very similar to each other. From these results, it is concluded that the high... 

From Fig. 6-4, shear thinning begins at a reduced shear stress of around 0.01, where the relative viscosity rjr is around 10. By definition of r]r, we have... 

Thomas (2008) defined EOR as a process to reduce oil saturation below the residual oil saturation (Sor). Recovery of oils retained due to capillary forces (after waterflooding in light oil reservoirs) and oils that are iimnobile or nearly immobile due to high viscosity (heavy oils and tar sands) can be achieved only by lowering the oil saturation below Sor. Such a case needs a definition of residual oil saturation different from the conventional one. 

The appearance of CMC s for polysoaps bearing particularly short hydro-phobic tails [193] is rather a semantic problem as these examples do not match the original definition of polysoaps anymore. If the hydrophobe tails are too short, no intramolecular aggregation can take place as evident from viscosity measurements [24, 133, 193], and intermolecular aggregation is needed to reduce hydrophobic interactions. 

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