Viscosity specific increase

This is the extra viscosity produced by the chain-molecules. Expressing it in terms of specific viscosity increase AVsp = v Mo > we get... 

In a great many papers published since 1930, Staudinger has tried to establish that the specific viscosity increase due to long-chain molecules in dilute solutions is proportional to their molecular weight and conforms to the equation ... 

Indeed this volume effect enters here only as a correction factor, in the case in which the macromolecular skein is relatively dense, so that the occluded solvent acts for a part as hydrodynamically immobilized. Takii the ideal case, that the occluded solvent is not immobilized, theoretically the- specific viscosity increase... 

It was observed that the solution-specific viscosity increases almost linearly with the polymer concentration. When gel should be formed directly at a definite site, the solution of both polymers containing a blocker is introduced, and upon removal of the blocker the gel is formed. Naproxen is easily entrapped by CD cavities this drug has a low toxicity and good tolerance and Is suitable for blocking the P-CD cavities. 

Temperature control is important in the handling and storage of isocyanates. Storage at inappropriate temperatures can cause product discoloration, viscosity increases, and dimerization. Handling personnel should consult the technical data sheets for the recommended storage temperature of the specific isocyanate product. 

As the temperature is decreased, free-volume is lost. If the molecular shape or cross-linking prevent crystallisation, then the liquid structure is retained, and free-volume is not all lost immediately (Fig. 22.8c). As with the melt, flow can still occur, though naturally it is more difficult, so the viscosity increases. As the polymer is cooled further, more free volume is lost. There comes a point at which the volume, though sufficient to contain the molecules, is too small to allow them to move and rearrange. All the free volume is gone, and the curve of specific volume flattens out (Fig. 22.8c). This is the glass transition temperature, T . Below this temperature the polymer is a glass. 

When assessing the potential for RO as an RW treatment option and reviewing standard plant specifications, it is important to compare the rated membrane capacity against the available water source to be treated. Reported RO membrane capacity may be based on a temperature of 77 °F (25 °C) and perhaps only a 1,000 ppm TDS RW. This level of TDS may be much lower than the potential source of RW and the temperature also may vary, making corrections necessary. At lower water temperatures, the viscosity increases and the RO flux decreases (output decreases). This increases the number of membranes required to provide the desired flow. 

The ionic strength dependence of intrinsic viscosity is function of molecular structure and protein folding, ft is well known that the conformational and rheological properties of charged biopolymer solutions are dependent not only upon electrostatic interactions between macromolecules but also upon interactions between biopolymer chains and mobile ions. Due electrostatic interactions the specific viscosity of extremely dilute solutions seems to increase infinitely with decreasing ionic concentration. Variations of the intrinsic viscosity of a charged polyampholite with ionic strength have problems of characterization. 

Pectin lyase (PNL) activity was measured spectrophotometrically by the increase in absorbance at 235 nm of the 4,5-unsaturated reaction products. Reaction mixtures containing 0.25 ml of culture filtrate, 0.25 ml of distilled water and 2.0 ml of 0.24% pectin from apple (Fluka) in 0.05M tris-HCl buffer (pH 8.0) with ImM CaCl2, were incubated at 37 C for 10 minutes. One unit of enzyme is defined as the amount of enzyme which forms Ipmol of 4,5-unsaturated product per minute under the conditions of the assay. The molar extinction coefficients of the unsaturated products is 5550 M cm [25]. Also viscosity measurements were made using Cannon-Fenske viscometers or Ostwald micro-viscosimeter, at 37°C. Reaction mixtures consisted of enzyme solution and 0.75% pectin in 0.05 M tris-HCl buffer (pH 8.0) with 0.5 mM CaCl2. One unit is defined as the amount of enzyme required to change the inverse specific viscosity by 0.001 min under the conditions of reaction. Specific viscosity (n p) is (t/to)-l, where t is the flow time (sec) of the reaction mixture and t is the flow time of the buffer. The inverse pecific viscosity (n p ) is proportional to the incubation time and the amount of enzyme used [26]. Units of enzyme activity were determined for 10 min of reaction. 

The molecular structure of polybutadiene prepared with BuLi and barium salts is greatly dependent on the presence of specific amounts of water and t-butanol used in the barium salt formation. The data in Figure 3 demonstrate that the greatest effect is obtained as the hydroxide content of the solution phase of the barium salt increased from 0 to 7.4 mole 7, Ba(0H)a. This particular salt results from a Hs0-t-butanol mixture containing 2.5 mole 7. water. The amount of trans-1,4 increased from 637, to 767, and accompanying this change the intrinsic viscosity increased from 1.60 to 5.22. The polymers were gel-free. 

Soy Protein Concentrates. Both non-functional (low or no solubility) and functional (good solubility, emulsification capacity, and dispersibility) soy protein concentrates (70% protein, dry basis) are commercially available for use in meat products (2-4, 6, j), 15) Normally, a highly functional product with no harsh or bitter flavors is desirable. When used to replace lean meat, non-hydrated concentrate can be used at levels up to 6-7% in finished nonspecific emulsion meats Higher replacement levels or formulas with specific cost/nutrition requirements may use soy protein concentrate with a judicious amount of textured soy protein (6). Excellent yields, cost savings, texture, flavor and nutrient profiles are possible. However, most soy protein concentrates lack sufficient solubility or sufficiently low viscosities to be used in brines for absorption or injection into whole muscle tissue. When legal standards for protein content exist (13), more concentrate must be used to achieve legal minimums. Brine viscosities increase and uniform distribution of brine components throughout the specific whole muscle piece is restricted. Finished product appearance and flavor are easily compromised. Thus, use of soy protein concentrates in whole muscle applications is limited. 

The viscosity of the solution is significantly increased when macromolecules are dissolved in a solvent. The specific viscosity of a solution t sp=(ri-r o)lr o expected to increase proportionally to the concentration c. The reduced viscosity rjgp/c still increases with increasing concentration. The data, however, can be extrapolated to zero concentration and results in the intrinsic viscosity, or the viscosity number [77], sometimes also called the Staudinger index... 

This increase in viscosity is all the more pronounced when the molecular weight of polymers is high. In Figure 6, is plotted against the concentration ratio, r, for the couple PAA-ISo OOO/PEO-750 000. In this system, when a < 3%, phase separation occurs, bulk solid particles appear and precipitate. So, no viscosity measurement is possible. For a 4% the specific viscosity of the mixture is very higher than the sum of viscosities of the two individtial polymer solutions. The comparison may be easier if we define another parameter the gain in viscosity, g, which is given by the relation ... 

A summary of the results obtained from GPC/DV on the first day and the third day after solution preparation is shown in Table II. For Red Oak and RO PO, the number average molecular weight decreased by approximately 6% from the first day to the third day. However, the intrinsic viscosities increased. According to traditional polymer solution theory (42), the product of intrinsic viscosity and molecular weight yields the hydrodynamic volume specifically, it has been shown that the molecular weight that... 

---