Hydrodynamic degradation

Kenis PR (1971) Turbulent flow friction reduction effectiveness and hydrodynamic degradation of polysaccharides and synthetic polymers J Appl Polym Sci 15 607... 

Note that to create length scales lower than those of proteins in water requires energy inputs of 1012W/kg, which is well above that achieved in bioprocessing. Thus, hydrodynamic degradation is only an issue in the production of large macromolecules, e.g., plasmid DNA. 

Hydrodynamic degradation by shearing through capillaries of polymer diluted solutions... 

In a recent version of the Tobolsky and Eyring formulation, the rate of mechanochemical degradation was considered as a Thermally Activated Barrier to Scission (TABS) process. The elastic energy function f(v /) was explicitly considered in terms of the frictional hydrodynamic drag force acting over the entire macromolecule [100]. A more detailed account of this model will be presented in Sect. 5.1. 

Chain degradation in turbulent flow has been frequently reported in conjunction with drag reduction and in simple shear flow at high Reynolds numbers [187], Using poly(decyl methacrylate) under conditions of turbulent flow in a capillary tube, Muller and Klein observed that the hydrodynamic volume, [r ] M, is the determining factor for the degradation rate in various solvents and at various polymer concentrations [188], The initial MWD of the polymers used in their experiments are, however, too broad (Mw/Iiln = 5 ) to allow for a precise... 

Because of the complex hydrodynamics associated with GPC systems, it is difficult to arrive at a simple correlation between GPC operational parameters and chain scission kinetics. At least five degradation mechanisms (given below with the associated flow field) may be operative in the different parts of the column, during a standard GPC analysis ... 

Wang X, Zhang Y (2009) Degradation of alachlor in aqueous solution by using hydrodynamic cavitation. J Fiaz Mater 161 202-207... 

Braeutigam P, Wu Z-L, Stark A, Ondruschka B (2009) Degradation of BTEX in Aqueous Solution by Hydrodynamic Cavitation. Chem Eng Tech 32 745-753... 

In order to check these results, Lutz et al. degraded polymer samples which had been isolated shortly before macrogelation, by ultrasonic waves [213]. Figure 38A shows the decrease of Mw and of the hydrodynamic diameter dz, measured by static and dynamic light scattering respectively, on ultrasonic treatment of a polymer of Mw = 2.2 X10. Both Mw and dz decrease first abruptly but then... 

The separation ability of the most common CE technique CZE is based on the hydrodynamic volumeicharge ratio, which makes it difficult to separate substances which are chemically very similar to the active ingredient such as by-products and degradation products. 

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