Viscosity optimization

Exclusion Chromatography in Dense Gases An Approach to Viscosity Optimization, J. C. Giddings, L. M. Bowman, Jr., and M. N. Myers, Anal. Chem., 49, 243... 

Edible, nontoxic and soluble in water (usual solvent, or ethanol) leading to a viscosity (optimal concentration) suitable for punping and spraying... 

In a single stage, without liquid recycle, the conversion can be optimized between 60 and 90%. The very paraffinic residue is used to make lubricant oil bases of high viscosity index in the range of 150 N to 350 N the residue can also be used as feedstock to steam cracking plants providing ethylene and propylene yields equal to those from paraffinic naphthas, or as additional feedstock to catalytic cracking units. 

Hexafluoiopiopylene and tetiafluoioethylene aie copolymerized, with trichloiacetyl peroxide as the catalyst, at low temperature (43). Newer catalytic methods, including irradiation, achieve copolymerization at different temperatures (44,45). Aqueous and nonaqueous dispersion polymerizations appear to be the most convenient routes to commercial production (1,46—50). The polymerization conditions are similar to those of TFE homopolymer dispersion polymerization. The copolymer of HFP—TFE is a random copolymer that is, HFP units add to the growing chains at random intervals. The optimal composition of the copolymer requires that the mechanical properties are retained in the usable range and that the melt viscosity is low enough for easy melt processing. 

To optimize the lesin system foi a given process and part, consideration should be given to fillers that can gready affect the cost and performance of the composite. Because of their low viscosity, fillers can often be added to polyesters. Fillers are often much cheaper than the resin they displace, and they can improve the heat resistance, stiffness, and hardness of the composite. Certain fillers, such as fumed siUca, impart thixotropy to the resin, increasing its resistance to drainage. 

The anion used to prepare the metal soap determines to a large extent whether it will meet fundamental requirements, which can be summed up as follows solubihty and stabiUty ia various kiads of vehicles (this excludes the use of short-chain acids) good storage stabiUty low viscosity, making handling the material easier optimal catalytic effect and best cost/performance ratio. 

Dmg loading can be accompHshed by dispersion or adsorption. In dispersed systems, a dmg is blended into a polymer by mechanical means, such as a kneader. The viscosity of the polymer, and the size and concentration of the dmg, need to be optimized to minimize aggregates. Dmgs can also be absorbed by equiUbrating a polymer in a dmg solution. The absorption rate can be accelerated by introducing an appropriate solvent to swell the polymer. AH solvents would then have to be removed. 

When selecting a suitable feed symp, the main criteria are optimization of enzyme productivity and minimization of the formation of by-products. Typical feed symp specifications are shown in Table 5. Higher symp concentration and higher viscosity results in a reduced isomerization rate due to diffusion resistance in the pores of the immobilized enzyme. A deaeration step is desirable to remove dissolved oxygen that would otherwise iacrease the formation of by-products. The pH is adjusted to the optimum level for the productivity of the enzyme. 

The target composition of the undesirable species in each MSA is assigned by the designer based on the specific circumstances of the application. The nature of such circumstances may be physical (e.g., maximum solubility of the pollutant in the MSA), technical (e.g., to avoid excessive corrosion, viscosity or fouling), environmental (e.g., to comply with environmental regulations), safety (e.g., to stay away from flammability limits), or economic (e.g., to optimize the cost of subsequent regeneration of the MSA). 

In order to achieve the best efficiency the SEC column should be operated at optimized operating parameters. The most important ones are flow rate [cf. van Deemter equation for band-broadening effects (21)], sample viscosity (depends on molar mass and concentration of the sample), and injection volume (7). 

Charged macromolecules, such as proteins or polymers, are often separated elec-trophoretically. The rate of migration through an electric field increases with net charge and field strength. Molecular size of analytes and viscosity of separation media both have inverse relationships with rate of migration. These variables must all be taken into account in order to optimize the conditions for an efficient electrophoretic separation. 

In manufacturing and processing polymer blends, it is thus important that the viscosity ratio be within the optimal range in the actual processing conditions. Not only the polymers to be blended but also the temperature and processing conditions (shear, elongation) should be carefully selected. Other factors, such as interfacial tension [46,47] and elasticity of the blended polymers, may also influence the blend morphology. 

Yet, some authors reported an increase, instead of reduction of viscosity after finishing treatment of filler [266, 267]. Plueddeman in [268] noted that increase or decrease of melt viscosity with finishing agents depends on what is the resultant reaction of the filler, agent and matrix - neutral, acid or basic. The viscosity may be optimized by using the right formulation. For example, agents with basic... 

Sadler, I.. Y. and Sim, K. G. Minimize Solid-Liquid Mixture Viscosity by Optimizing Particle Size Distribution, Chem. Eng. Prog, V. 87, No. 3, 1991. 

The combination of highly exothermic reactions with a sharp increase in viscosity as conversion proceeds controls reactor design and operational conditions in full-scale operations. The art of sulfonation is to maintain the optimal reaction temperature and reaction time, resulting in products with small amounts of byproducts and good color. 

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