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How Temperature Affects Viscosity
How Temperature Affects Viscosity: Viscosity can be defined as the internal friction that occurs as a material flow, relative to itself....
2017年11月14日星期二
Using Ubbelohde viscometer one-point method to determine the intrinsic viscosity
Material: a triangular flask
Two 10ml pipettes
Ubbelohde viscometer (capillary 0.5mm)
A water bath (temperature control accuracy of ± 0.1 ℃)
A stopwatch
Rubber hose two sections
A syringe
Wash the ear ball one
The company is located in:
step:
1, the system solution: Take a certain amount of polymer, add 10mm solvent, make it completely dissolved, if necessary, heated.
2, constant temperature: installed device, stable temperature up and down changes 0.1 ℃.
3, plus the solution balance 5min: up and down into the capillary tube three times.
4, determination: measured three sets of data, so that the deviation but 0.2s.
5, Determination of solvent flow time.
data processing:
ηr = t / t0 (t is the solution flow time, t0 solvent time)
ηsp = ηr-1
[η] = [2 (ηsp-ηr)] / C (C is the concentration unit g / ml)
[η] = (ηSP / C) c = 0 = (ln ηr / C) c = 0 [η] = KMα
Remove the pipette has been pre-heated solution 10ml, into the viscometer, the same method, the installation of viscometer, the determination of the solution outflow time t. Then followed by adding 2.00,3.00,5.00,10.00 ml of distilled water.
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2017年7月24日星期一
Determination of Molecular Weight of Polyacrylamide by Dilute Solution Viscosity Method
Determination of
Molecular Weight of Polyacrylamide by Dilute Solution Viscosity Method
Abstract: To learn and master the Ubbelohde
viscometer viscosity measurement method; to understand the statistical
significance of the molecular average molecular weight and polymer dilute
solution of the intrinsic viscosity of the characterization method; master the
determination of polymer dilute solution viscosity experiment Technology and
viscosity method to characterize the molecular weight of polymer; the viscosity
of polyacrylamide aqueous solution to reflect the molecular weight of
polyacrylamide;
Experimental principle
Liquid flow is due to external force molecules irreversible displacement
process. Liquid molecules exist between the interaction force, so when the
polymer liquid flow, the polymer molecules to produce internal friction between
the performance of the liquid viscosity characteristics.
According to Newton's law of viscous flow, the viscous resistance of the liquid
to the flow is caused by the flow gradient between the two layers of flowing
liquid (with A) due to intermolecular friction.
In the
Ubbelohde viscometer capillary, it is assumed that the force that causes the
polymer dilute solution to flow is all used to overcome the internal friction
f:
For most flexible polymer - good dilute solution
solvent system, protraction
with c. Extrapolated intercepts coincide with the value of the point 
Instrument: Ubbelohde viscometer constant
temperature water bath, electronic scales, stopwatch, pipettes, flasks, ear
cleaning ball, glass sand funnel;
Reagents: polyacrylamide samples, sodium
chloride, purified water;
Experimental steps:
1. Solution preparation
2. Viscosity meter cleaning and drying
3. Viscometer installation: check the
viscometer, with a clamp carefully fixed viscometer, into the constant
temperature sink. The viscometer should be kept vertical, and the constant
temperature surface should be immersed in the two balls above the capillary and
the temperature remains constant.
4. Determine the elution time of the solution:
Remove the 10 ml solution from the self-volumetric flask and inject it from the
A tube into the viscometer. The clip holds the C tube and draws the solution
from the B tube to the top of the a The ball volume of half of the time until
the release of the ear ball, release the C tube clip, the air into the C tube,
immediately horizontally watching the decline in the liquid level with a
stopwatch recorded liquid flow through the a and b line time is Out of time.
5 ml, 5 ml, 10 ml and 10 ml of solvent were
added to the same solution for 2/3, 1/2, 1/3, 1/4 of the original solution, and
the respective elution times (t2, t3 , T4, t5).
Determination of pure solvent elution time: The
solution in the viscometer was poured out and washed several times with solvent
to determine the elution time t0 of the pure solvent.
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Coyp right by @Hangzhou Zhongwang Technology CO.,LTD
2017年7月18日星期二
Difference Between Ubbelohde Viscometer and Brookfield Viscometer
Difference Between Ubbelohde Viscometer and Brookfield Viscometer
Abstract：Introducing of Ubbelohde viscometer and
Brookfield Viscometer. Concept, difference and advantages of ubbelohde
viscometer and Brookfield viscometer.
Brief introduction of Ubbelohde
viscometer：
The molar mass of the polymer not only reflects the size of the polymer molecule, but also directly related to its physical properties, is an important basic parameter. Unlike conventional inorganic or low molecular organic matter, the polymer is mostly macromolecular mixture of different molar mass, so the measured molar mass of polymer is usually a statistical average.
Brief introduction of Brookfield Viscometer:
Brookfield Engineering is an engineering and manufacturing company with headquarters in Middleboro, Massachusetts. Its product line includes laboratory viscometers, rheometers, texture analyzers, and powder flow testers as well as in-line process instrumentation. These instruments are used by research, design, and process control departments. It was suspected of causing one of Massachusetts' most unusual and serious residential toxic waste contamination problems, and settled the claim by paying relocation and cleanup costs without admitting responsibility.
Classical Brookfield viscometers employ the
principle of rotational viscometry - the torque required
to turn an object, such as a spindle, in a fluid indicates the viscosity of the
fluid. Torque is applied through a calibrated spring to a disk or bob
spindle immersed in test fluid and the spring deflection measures the viscous
drag of the fluid against the spindle. The amount of viscous drag is
proportional to the amount of torque required to rotate the spindle, and thus
to the viscosity of a Newtonian fluid.In the case of non-Newtonian fluids,
Brookfield viscosities measured under the same conditions (model, spindle,
speed, temperature, time of test, container, and any other sample preparation
procedures that may affect the behavior of the fluid) can be compared. When
developing a new test method, trial and error is often necessary in order to
determine the proper spindle and speeds. Successful test methods will deliver
a % torque reading between 10 and 100. The rheologicalbehavior
of the test fluid can be observed using the same spindle at different speeds,
but because the geometry of the fluid around a rotating bob or disk spindle in
a large container does not allow a single shear rate to
be assigned, proper rheometry is not feasible using this setup.
Apart from its rotating bob viscometers, Brookfield now also
produces defined-geometry rheometers which allow complete rheological analysis
of fluids.
Difference Between Ubbelohde Viscometer and Brookfield Viscometer
1. Ubbelohde Viscometer：Cheap, suitable for relative measurement, Uptel viscometer itself can not control temperature, with precision thermostat can be accurate measurement of viscosity, in addition to the Ubbelohde viscometer installed in the automatic viscosity test equipment, you can achieve Ubbel's viscosity Automatic measurement, directly to the intrinsic viscosity, than the viscosity, relative viscosity, viscosity, viscosity average molecular weight and other needs of the measurement results.
2. Brookfield Viscometer：Have adopted the well-known viscosity measurement principle, which absorbs the viscosity value by the continuous rotation of the rotor immersed in the liquid to be measured. The torque is proportional to the resistance of the rotor immersed in the sample by sticky dragging, proportion.
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Coyp right by @Hangzhou Zhongwang Technology CO.,LTD
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