Viscosity Brookfield

Shear thinning and thixotropic properties of non-Newtonian materials at the shear rate ranging from 0.1 to 50 s can be measured by the standardized method. The standard describes three methods of measurement. Method A is used to measure apparent viscosity of material by measming torque with spindle rotating at constant speed. Apparent viscosity in centipoises (equal to mPa.s) is calculated by multiplication of scale reading of viscometer by a scale factor, which depends on the spindle number and rotation speed. If the material is Newtonian, its viscosity does not depend on shear rate and measurement at one speed is sufficient. Non-Newtonian materials require measurements at different shear rates as described in methods B and C. 

Method C involves application of high speed disperser (2000 rpm) to shear out the structure. This method is also used to estimate shear thinning and thixotropy. 

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Butyl latices have a solids content of about 60 wt%, a pH about 5.5, a Brookfield viscosity near 2.5 Pa s and an average particle size of 0.3 p,m. 

Figure 13. Effect of OLOA-1200 concentration (parts of OLOA-1200 per 100 parts carbon black) on the Brookfield viscosity (at 30 r.p.m.) of dispersion of carbon black in paraffin oil.

Synthesis of a Urethane Vinyl Ether Oligomer. A urethane vinyl ether oligomer was prepared by the procedure discussed by Lapin.15 Reacting a hydroxyalkyl vinyl ether, an oligomeric diol and a diisocyanate gave and oligomer that had a Brookfield viscosity of 3.7 million mPa-s and a theoretical equivalent weight of 1000 g per vinyl ether double bond. 

Oligomer and Film Characterization. Brookfield viscosity measurements were taken on a Model RVTD digital readout viscometer. Samples for Instron testing were prepared on glass plates using 25 or 75 pm (1.0 or 3.0 mil) Byrd film applicator. Coatings for cure speed and MEK double rub (MEKDR) studies were prepared on aluminum Q-Panels using a 40 wire wound rod (100 pm or 4.0 mil). 

The equivalent weight increased from 210 for UPE A to 316 for UPE E with one third of the maleic anhydride was replaced with succinic anhydride and 634 for UPE F with two thirds of the maleic anhydride is replaced with succinic anhydride. This change will effectively decrease the crosslink density of the final cured film. The Brookfield viscosities of the two new polyesters (E and F) are less than those from the first series. Since the molecular weights should be about the same (1760), it is not surprising that the Brookfield viscosities were relatively constant for all three unsaturated polyesters. The slight decreasing trend in viscosity with increasing succinic anhydride in the unsaturated polyester may be due to the increased free volume obtained when succinic anhydride is substituted for maleic anhydride. 

Brookfield viscosity measurement is a way to estimate the quality of a fresh dispersion. The ageing test controls the evolution of the viscosity over time. It is... 

Brookfield Viscosity A measurement of the apparent viscosity of a fluid using a Brookfield viscometer. This viscometer is a variable-sheer, variable-rpm viscometer. 

A reactor charged with sulfopropyldimethylammoniumethyl methacrylate (0.020 mol), a-methoxy-co-methacrylate polyethylene glycol 1000 (0.009 mol), water (398 g), and ethanol (261.90 g) was heated to 78°C. The mixture was then simultaneously treated with ammonium persulfate (0.004 mol) dissolved in water (20 g) over 150 minutes, ammonium persulfate (2.5 g) dissolved in water (60 g) continuously over 120 minutes, sulfopropyldimethyl-ammoniumethyl methacrylate (0.182 mol) over 120 minutes, and a-methoxy-w-meth aery late polyethylene glycol (0.078 mol), and water (205.80 g). Thereafter the reaction was maintained at 70°C for 90 minutes and then cooled. The solution was then treated with water and ethanol removed by distillation. The product was isolated with a solids content of 27.3%, a pH of 2, a Brookfield viscosity of 36 mPa s, and an Mw of 65,000 Da with an M of 8000 Da. 

BROOKFIELD VISCOSITY OF GUM ARABIC vs. STARCH OCTENYLSUCCINATE AS A FUNCTION OF CONCENTRATION... 

Hydroxide A/HEC molar ratio Hydrophobe Hydrophobe MS Alkylation efficiency 1% Brookfield viscosity... 

BROOKFIELD VISCOSITY OF 21 CONTROL LATEX Journal of Applied Polymer Science... 

The saponification of a ceric-initiated starch-g-PAN was likwise examined at the different ethanol-water ratios, and these results are also shown in Table III. Once again, solubilities were determined for undried water dispersions after exhaustive dialysis. Brookfield viscosity was not used as a measure of crosslinking for these HSPAN preparations, because individual gel particles could not absorb all of the available water at 0.22% solids and thus could not exist in... 

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