Stability shear

Bosch Injector Rig measuring the mechanical stability of the oil to assess its shear stability. 

It has been shown that hydrogen bonding-mediated interpolymer complexes can be powerful drag reducers. The drag-reduction levels in such polymer systems increase dramatically by a factor of 2 to 6 when compared with their nonassociating polymeric precursors. Their shear stability is also shown to be significantly enhanced [1156]. 

The aim of the present paper is to report on the solution structure of polymers, to show how structure-property relationships can be derived in a simple manner, so that they can be used for technical applications. Some predictions will also be made concerning the viscous and elasticity yield as well as polymer shear stability. To demonstrate these theoretical predictions narrowly distributed polystyrene samples will mainly be used as examples. 

Prediction of Viscoelastic Properties and Shear Stability of Polymers in Solution 17... 

Grest, G.S. Normal and Shear Forces Between Polymer Brushes. Vol. 138, pp. 149-184 Grigorescu, G, Kulicke, W.-M.t Prediction of Viscoelastic Properties and Shear Stability of Polymers in Solution. Vol. 152, p, 1-40. 

Shear stability undergoes irreversible shear degradation reversible shear thinning. 

There has been a trend towards so-called multifunctional softeners in which account is taken of various other factors such as hydrophilicity, sewability, antistatic behaviour, lubrication and shearing stability [482]. For example, in jet dyeing a product will require, in addition to softening power ... 

E. Davies, E. Dickinson, and R. Bee Shear Stability of Sodium Caseinate Emulsions Containing Monoglyceride and Triglyceride Crystals. Food Hydrocolloids 14, 145 (2000). 

An outstanding property of these polymers is their shear stability. The sonic shear stability testsfci indicate that these polymers are superior to some of the currently used polymers of ethylene-propylene or methacrylate type. The excellent stability of the hydrogenated diene-styrene polymers is attributed to their relatively low molecular weight and narrow distribution consistent with the established theory of shear degradation of polymers. The most recent developments in this field are block polymer VI improvers with dispersancy properties, built into the molecule by chemical modification of the rubber block. 2... 

The effect of irradiation on the shear stability of Polyox solutions is shown in Figure 3. The viscosities before agitation were comparable, and it is apparent that after doses of approximately 0.4 megarad the solutions are much more stable than the unirradiated control. 

Figure 3. Effect of 2-m.e.v. electron radiation on shear stability of Poltjox solution. 5% aqueous solutions prepared from dry irradiated polymer...

Obviously, this approach does not only take into consideration the influence of the molecular weight and concentration, but also the contribution of the solvent power on the state of solution. With these shear stability criteria, it is therefore possible to make ad hoc predictions on the basis of the data of the single chain, which can be taken from handbooks in many cases. In addition, it should be noted that theoretical forecasts fit the experimental data very satisfactorily (Kulicke, Kniewske 1986). 

Bouldin M, Kulicke W-M, Kehler H (1988) A prediction of the non-Newtonian viscosity and shear stability of polymer solutions Colloid Polym Sci 266 793... 

Deshmukh SR, Singh RP (1987) Drag reduction effectiveness, shear stability and biodegrada-dation resistance of guargum-based graft copolymers J Appl Polym Sci 33 1963... 

Evans AP (1974) A new drag-reducing polymer with improved shear stability for non-aqueous systems J Appl Polym Sci 18 1919... 

Kulicke W-M (1987) Prediction of viscosity level in the non-Newtonian range and shear stability of polymer fluids Proceed 2nd Plym Symp, 42, Napa Valley, USA... 

Reddy GV, Singh RP (1985) Drag reduction effectiveness and shear stability of polymer-polymer and polymer-fiber mixtures in redrculatory turbulent flow of water Rheol Acta 24 296... 

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