EXPERIMENT 1
Surface tension determination
with the maximum differential
pressure method
Wang Zengbao
2012.11
1. Experimental purposes
(1)Master the principles and methods of maximum
differential pressure method for the determination of
surface tension.
(2)Measure the surface tension of n-butyl alcohol solution,
and understand the concept of surface tension and
influencing factors.
(3)Learn Gibbs equation and its applications.
2. Experimental principles
Polyacrylamide can be synthesized from acrylamide
triggered by ammonium persulfate:
(NH4)2S2O8
nCH2 CH
CONH2
[CH2 CH]n
CONH2
Polyacrylamide can hydrolyze in alkaline solution, which
generates partially hydrolyzed polyacrylamide:
[CH2 CH]n
+ yH2O + zNaOH
CONH2
[CH2 CH]x
[CH2 CH]y
CONH2
COOH
[CH2 CH]z + (y + z)NH3
COONa
2. Experimental principles
2
P 
R
P

R
P1
P2
1
2
R
2 2
p2 
r
2 1
p1 
r
p2
2 
  1 （1）
p1
P —The additional pressure
which is formed when the
water drops down in the wide
mouth bottle

—The surface tension
R
—The curvature radius of
（N/m）
the bubble
2. Experimental principles
2
P 
R
2 2
p2 
r
2 1
p1 
r
p2
2 
  1 （1）
p1
Therefore, at the same temperature, once the ΔP1, ΔP2 are measured, and
the IFT of the liquid(water) whose IFT is known is found out according to
the temperature table,then we can calculate the IFT of the unknown liquid
from the formula 。
3.Apparatus and reagents

Apparatus

One set of device to measure the IFT with the
method of maximum differential pressure,Bottle,
rubber pipette bulb.

Reagents

N-butyl alcohol (analytically pure), distilled water.
4.Experimental procedures

(1)Wash the external case and the capillary tube of the
instrument used to measure surface tension with lotion. First
add a little lotion into the external case,rotation it inclined so
that the lotion can contact with the external case(be careful not
to let the lotion outflow from the side of the tube).Then insert
the capillary tube and maintain the inclined external case
still.Rotate the capillary tube to make the lotion contact with the
capillary tube.Adsorb some lotion with the rubber pipette bulb
to the capillary tube to wash the inside of the capillary tube.Pull
the spent lotion to its original bottle and wash the external case
and the capillary tube with running water fully.Finally,wash the
external case and the capillary tube with distilled water three
times respectively.Then we can go on with the following
experiences.
4.Experimental procedures

(2)Put some distilled water into the external
case(regard as liquid of known IFT. See Appendix II
to get its surface tension).Insert the capillary tube into
the external case and plug the plug tightly and let the
tip of the capillary tube touch the liquid surface
exactly.Read out the zero level h0 of the tube beneath
the inclined tube manometer(At this point both ends
of the inclined tube manometer connect with the
atmosphere).Install the device according to figure21,where the separatory funnel is filled with tap water..
4.Experimental procedures

(3)Open the piston of the separatory funnel to let the water
in it drip slowly into the wild-mouth bottle.Then the
pressure inside the bottle increase gradually and bubbles
will pass through the end of the capillary tube.

Read out the highest level h1 from the inclined tube
manometer when the first bubble pass through it.Repeat
the same procedures three times and calculate the average
value h2.
4.Experimental procedures


(4)Drain the distilled after the maximum differential
pressure has been measured.Wash the external case and the
capillary tube once with butanol with the concentration of
0.002mol/L.Then add the solution and measure its
maximum differential pressure just like the distilled
water.Measure the maximum differential pressure of the
butanol solution with the concentration of
0.05,0.10,0.15,0.20,0.25,0.30,0.35mol/L .
(Note: every time the solution is changed, we should use the
Pending liquid to wash the external case and the capillary
tube)
(5) Record the experimental temperature.
5.Experimental results processing

(1)Isolate the surface tension of distilled water at
experimental temperature from the appendix.

(2)Calculate the surface tension of solution with different
concentration of normal butyl alcohol by   p  
2
2


p1
2
(3)Using surface tension as vertical ordinate,concentration
as horizontal scale,draw the б-c figure of nomal butyl
alcohol solution on the coordinate paper.
(4)Select some points from theб-c figure and draw the
tangents of different concentration curve .Then calculate
the surface adsorptive capacity according to the Gibbs
equation ;and draw the isothermal adsorption curve of
nomal butyl alcohol solution
6.Questions

(1)During experiment ,if the capillary insert the liquid
surface by 1mm ,how much error will bring about?

(2)During experiment ,why do we slow the barbotage ?

(3)During experiment,why do we measure the surface
tension of different concentration solution from from low
to high.
EXPERIMENT 3
Preparation and electrophoresis of
colloids
Wang Zengbao
2011.4
1. Experiment purposes
（1）Learn
the basic principles of preparation of
sol (colloid), and master the main methods of
preparation sol;
（2）Mensurate
the electrokinetic potential of
AgI (silver iodide) sol by measuring the movement
of interface.
2. Experiment principles
Colloidal sol is a highly dispersed system with solid of
very small solubility dispersing in liquid. Its diameter
changes in the range of 10-7 to 10-9 meter.
The formation of stable colloidal material involves two
facets: the dimension of the dispersed phase within the
colloidal range; the particles dispersed in liquid should not
aggregate, so stabilizing agent usually added.
Basically, the preparations of colloidal systems involve
either degradation of bulk matter or aggregation of small
molecules, ions or particles.
2. Experimental principles

Electrophoresis of colloids

Under an external electric field the colloidal particles
moving to the positive electrode or negative electrode, this
phenomena is called electrophoresis.
Electrophoretic potential can be measured by
electrophoresis through two methods: microscopic method
and macroscopic method.

3.Apparatus and reagents

Apparatus

Electrophoresis apparatus; Electrophoresis tube;
Stopwatch; Pt electrode, 2; 100mL Beaker, 3;
Plastic head dropper ,2;25mL Graduated flask,
2 , and so on.

Reagents

Silver nitrate solution (0.01mol/L); Potassium
iodide solution (0.01mol/L); Potassium chloride
solution (0.005mol/L)
4.Experiment procedures


Preparation of AgI negative solution
20mL 0.01mol/L KI (Potassium iodide) solution is
added to a 100mL beaker, 18.7mL 0.01mol/L
AgNO3 (Silver nitrate ) solution is dropwise added
to the beaker under stirring, AgI negative colloid
is prepared.
4.Experiment procedures

Determination of potential

(1) The electrophoresis apparatus should be washed clean
(2) Fixed the electrophoresis apparatus vertically on the iron
support stand
(3)Close the piston, Add colloid through the funnel with plastic
head dropper
(4) Assistant solution is added into the U-tube
(5) Open the piston slowly, when colloid up to 0-tick，close the
piston
(6)Gently insert two electrodes, immerge assistant solution 1cm
(7)Push the electrophoresis apparatus’s “start” button, and
record the time that the interface rising 0.5, 1.0, 1.5 cm cost with
a stopwatch.
(8)Turn off the power, measured the distance of two electrodes
by a ruler. Wash the apparatus







5.Experiment results processing

（1）Summarize the method of preparation of
colloid;

（2）Calculate ξ potential of AgI negative
colloid.
6.Questions




（1）What are the similarities and differences among
different preparation methods?
（2）Why must the conductivity of the assistant solution
be equal to that of the colloid? What is the function of that
for calculating the potential?
（3）What are the reasons that cause the color, definition
and moving speed differences between the rising interface
and declining interface?
（4）What are removed through dialysis of Fe (OH)3? Is
there any way to detect degree of purification? Is it to
remove all the ions dispersed in the solution during dialysis?
EXPERIMENT 4
Coagulation of Inorganic Electrolyte and
Flocculation of High Molecule Polymer
Geng Jie
2012.11
1. Experiment purposes
(1)
Master principle and method of sol coagulation.
(2)
Verify coagulation symbol and valence number
rule of electrolyte.
(3)
Understand the flocculation of the watersoluble polymer to the sol.
2. Experiment principles
(1) Coagulation of inorganic electrolyte
The entire process that the sol losses coagulation stability
and then losses dynamic stability is called coagulation. The
sol can be caused to coagulate by electrolyte. The reason is
that the electrolyte can decrease ξ potential of sol, and the
higher electrolyte concentration, the lowerξpotential is.
When theξpotential drops to a certain value, the sol will
lose coagulation stability, and then will occur coagulation.
The higher ion valence number of opposite sign, the
greater coagulation ability of electrolyte is. This is
consistent with SchlZe--Hardy Rules.
M+:M2+:M3+＝（25～150）∶（0.5～2）∶（0.01～0.1）
2. Experimental principles
(2) Mutual coagulation phenomena

The mutual coagulation phenomenon is that mixing the
two sols with the opposite electric charge can also cause
coagulation. There are usually two mechanisms.

Electric nature neutralization about two kinds of sol
particles of opposite electric charge.

A sol with high counter-ion of opposite electric charge sol.
2. Experimental principles
(3) Flocculation of high polymer
When the concentration of polymer is very low, main
manifestation of polymer is flocculation for sol.
Flocculation is created due to "bridging" of polymer to sol
particles. "Bridging" theory: When the concentration of
polymer is very low, polymer chains can be absorbed on
several colloidal particles at the same time. Several
particles join together through "bridging". Due to rotation
and vibration of polymer chains, colloidal particles join
together and subside.
3. Instruments and Chemicals




Instruments
722 spectrophotometer, 100mL conical flask, 10mL
micro-burette, 5mL pipette, 10mL pipette, 10mL test
tube, 20mL test tube, 50mL plug graduated cylinder,
50mL beaker, 100mL beaker.
Chemicals
0.01mol/L KCl, 0.001mol/L K2SO4, 0.001mol/L
K3(COO)3C3H4OH, Fe(OH)3 sol，clay sol.
4.Experiment procedures

(1) Coagulation of electrolyte to sol

In the three clean, dry 100mL conical flasks, add
10mL Fe (OH)3 sol with pipette respectively. Then
instill electrolyte solution listed in Table 4-1 with
micro-burette respectively, and add each drop with
fully oscillation. Sol does not appear roily at least one
minute before adding the second. Record the volume
of electrolyte solution when just appear roily, and list
in Table 4-1.
4.Experiment procedures

Table4-1 coagulation record about different electrolytes to sol
Fe(OH)3 sol
electrolyte
KCl
K2SO4
K3(COO)3
C3H4OH
concentration of
volume of all electrolyte coagulation value
electrolyte solution(mol/L) solution(mL)
(mmol/L)
4.Experiment procedures

(2) Mutual coagulation between clay sol and Fe(OH)3 sol

Take six dry test tubes, and add the amount of Fe (OH)3 sol
according to Table 4-2 in each test tube. Then add the clay
sol in all test tubes, so that the total volume of the sol is 6mL
in each test tube. Shake each test tube, rest 10 minutes, and
record the coagulation phenomena of each test tube.
4.Experiment procedures

Table4-2 the record sheet about mutual coagulation of sols
test tube
number
1
2
3
4
5
6
Fe(OH)3
sol
0.1
0.5
1
3
5
5.5
clay sol
5.9
5.5
5
3
1
0.5
coagulation
phenomena
4.Experiment procedures

(3) Flocculation of high polymer
Take three 50mL plug graduated cylinder with similar internal
diameter, respectively add 30mL clay sol with pipette, respectively
add the 0.02% partially hydrolyzed polyacrylamide (HPAM)
solution of 2×106 molecular weight 2drops﹑10drops and
40drops and fro turn 10 times, rest 2 minutes, draw 5mL solution
at 2cm department under the surface, with 722 spectrophotometer
(the Appendix eight), at the wavelength of 420nm, measure optical
density with the distilled water as blank, and fill the data into
Table 4-3.
4.Experiment procedures

Table4-3 the record sheet of flocculation about HPAM to clay sol
clay sol
HPAM 0.02％
30 mL
30 mL
30 mL
30 mL
0
2d
10d
40d
C% system concentration
of HPAM (％)
T (T=I/I0)
D (D=-LogT)
Ar (Ar=D/D0)
*Ar is the ratio of sol optical density with HPAM and without HPAM. If Ar=1,
that is not complete flocculation and if Ar = 0, that is complete flocculation. So
Ar can show the degree of flocculation.
4.Experiment procedures

(3) Flocculation of high polymer
In this study, the volume of HPAM added is not fixed, only for
reference. Because the best flocculated concentration change with
the molecular weight of HPAM, degree of hydrolysis, the sol
concentration and preparative conditions. Therefore, the amount
of HPAM added can make appropriate changes based on the
actual situation.
5.Experiment results processing

(1) Particularly observe various phenomena in
experiment, record these phenomena and data
and fill in the form with the data.

(2) According to the results, determine the electric
nature of Fe (OH)3 sol and clay sol.

(3) Compare the coagulation values of different
electrolytes, and verify SchlZe–Hardy law.

(4) Draw up Ar-c curve with the quality
percentage of HPAM as X-axis and flocculation
efficiency Ar as Y-axis, and explain it..
6.Questions

(1) Why must the Fe (OH)3 sol go through dialysis
before flocculation test?

(2) Whether is the coagulation values of different
electrolysis to the same sol same? Why?

(3) When the concentration of polymer is higher in
the sol, what will arise, and why?
EXPERIMENT 5
Preparation identification and
breakdown of emulsion
Wang Zengbao
2012.12
1. Experimental purposes
（1） Preparation of different types of emulsion;
（2） Understand some method of the emulsion
preparation;
（3） Familiar with some damage emulsion
method.
2. Experimental principles
Emulsion is a liquid dispersed in another immiscible
liquid in the form of dispersion. There are two types of
emulsion, namely oil in water type (O/W) and oil-water type
(W/O). Only two immiscible liquids can not form a stable
emulsion. To form a stable emulsion, emulsifier must exist.
In general emulsifiers are mostly surface active agent.
Surfactant could reduce the surface energy and form
protective film of the droplet surface, or make the droplet
surface charged to stabilize the droplet emulsion.
2. Experimental principles
Emulsifiers could also be divided into oil in water
emulsifier and oil-water emulsifier. Generally monovalent
metal fatty acid soap (eg sodium oleate) is hydrophilic than
hydrophobic, so it’s oil in water emulsifier. Divalent or
trivalent fatty acid soap (such as magnesium oleic acid) is
lipophilic than hydrophilic, so is the water-in-oil emulsifier.
The following three methods could identify the two types
of emulsions:
（1）Dilution
（2）Conductivity method
（3）Staining
2. Experimental principles
（1） Dilution
Add one drop of emulsion in the water, if it spreads out
immediately, it means that the dispersion medium is water,
so it is oil in water emulsion; And it is water in oil emulsion
if it is not immediately disperse.
2. Experimental principles
（2） Conductivity method
Water phase generally contains ions, so its conductivity is
much greater than the oil phase. When the water medium is
dispersion medium (continuous phase), the conductivity of
emulsion is large; the other hand, if oil is continuous phase and
water is the dispersed phase, water droplets are not continuous,
so the conductivity of emulsion is weak. Two electrodes which
are connected to DC power supply and ammeter are inserted
into the emulsion solution. If there is significant deflection of
ammeter, the emulsion is oil in water solution; if the pointer
does not move, the emulsion is water in oil emulsion.
2. Experimental principles
（3） Staining
The dye which is only soluble in oil but does not dissolve
in water or only water-soluble (such as Sudan Ⅲ which is red
dye and only soluble in oil but not water-soluble) is added
into the emulsion. If the dye dissolved in the dispersed phase,
the droplets stained one by one appears in the emulsion. If
the dye is soluble in the continuous phase, the emulsion
showed uniform dye colors inside. The type of emulsion could
be determined by the dispersion of dye.
2. Experimental principles
Methods of destroy the emulsion
(1) Adding the demulsifier
(2) Adding electrolyte
(3) Heating
(4) Electrical method
2. Experimental principles
（1）Adding the demulsifier
Demulsifier is often anti-emulsifier. For example, the
water in oil emulsion made by adding magnesium oleic acid
could be broken by adding sodium oleate. The sodium oleate
which is hydrophilic could adsorb on the liquid surface and
form the hydration shell that could reduce the emulsification
of magnesium oleic acid and break the emulsion. If adding
excess sodium oleic acid, the water in oil emulsion may
change into oil in water emulsion.
2. Experimental principles
（2） Adding electrolyte
Different electrolytes may have different effects. In
general, by adding electrolytes into oil-in-water emulsion,
it could change HLB of the emulsion and reduce the
stability of the emulsion. .
2. Experimental principles
（3） Heating
Elevated temperature could reduce the emulsion agent
adsorption on the interface and thin the solvent layer and
low the medium viscosity and enhance the Brownian motion.
Therefore, reducing the stability of emulsion helps emulsion
damage.
（4） Electrical method
Under the action of the high voltage field, droplet could
deform and connect to each other, then decreased dispersion
results in the destruction of the emulsion .
3. Equipment and medicine

Equipment

100mL conical flask with a plug 2, Large test tube 5,
25mL graduated cylinder 2, 100mL beaker 3, Small
dropper 3, constant current source 1, milliammeter 1,
one pair of electrodes

Medicine

Benzene (chemical pure), Sodium oleate (chemical pure),
3mol/L HCl solution, 1%, 5% sodium oleate solution, 2%
magnesium oleic acid benzene solution , 0.25mol/LMgCl2
aqueous solution, saturated NaCl solution, Sudan Ⅲ
solution.
4.Experimental procedures

（1） Preparation of emulsion

Add 15mL 1% aqueous solution of sodium oleate into 100mL
conical flask with a plug. Then add 15mL of benzene (each of
adding about 1mL) with severe shaking after each adding of
benzene until there is no benzene layer phase. Type
Ⅰemulsion is obtained.

15mL 2% benzene solution of sodium oleate is added into
another 100mL conical flask with a plug. Then 15mL of water
is added (each of about plus 1mL) with severe shaking after
each add of water until there is no water layer phase. Type Ⅱ
emulsion is obtained.
4.Experimental procedures

（3） Destruction and phase conversion
of the emulsion

①Take two clean test tube, add 1 ~ 2mL typeⅠ and type
Ⅱ emulsion to each test tube, dropwise add 3mol/L HCl
solution, then observe the phenomenon.

②Take two clean test tube, add 1 ~ 2mL type Ⅰ and type
Ⅱ emulsion to each test tube, heat the tubes in water
bath, then observe the phenomenon.
4.Experimental procedures

（3） Destruction and phase conversion
of the emulsion

③Take two clean test tube, add 2~3mL typeⅠ and type
Ⅱ emulsion to each test tube, dropwise add 0.25mol/L
MgCl2 solution with severe shaking after each add of
MgCl2 solution, then observe the destruction and phase
conversion of the emulsion. (Identify the phase
conversion using dilution method, the same below)
4.Experimental procedures

（3） Destruction and phase conversion
of the emulsion

④Take two clean test tube, add 2~ 3mL typeⅠ and type
Ⅱ emulsion to each test tube, dropwise add saturated
NaCl solution with severe shaking after each add, then
observe the destruction and phase conversion of the
emulsion.
⑤Take two clean test tube, add 2~ 3mL typeⅠ and type
Ⅱ emulsion to each test tube, dropwise add 5% sodium
oleic acid solution with severe shaking after each add,
then observe the destruction and phase conversion of the
emulsion.

5.Experimental results processing

Record and collate the phenomena observed in
experiments, and analyze causes.
6.Questions




1. What is common point for the various emulsion
identification methods?
2. It is said that if the water is more than oil it could form
oil in water emulsion, whereas the water-oil. Is it right or
wrong? Illustrate it by trial results.
3. Could the phase conversion method be used as
demulsification? Could the demulsification method be used
as phase conversion?
4. Could the two immiscible liquids form emulsion
automatically by adding emulsifier?
EXPERIMENT 6
Synthesis and hydrolysis of
polyacrylamide
Wang Zengbao
2011.4
1. Experimental purposes
1.Be familiar with addition polymerization by the
synthesis of polyacrylamide from acrylamide.
2. Be familiar with the hydrolysis of
polyacrylamide in alkaline solution.
2. Experimental principles
Polyacrylamide can be synthesized from acrylamide
triggered by ammonium persulfate:
(NH4)2S2O8
nCH2 CH
CONH2
[CH2 CH]n
CONH2
Polyacrylamide can hydrolyze in alkaline solution, which
generates partially hydrolyzed polyacrylamide:
[CH2 CH]n
+ yH2O + zNaOH
CONH2
[CH2 CH]x
[CH2 CH]y
CONH2
COOH
[CH2 CH]z + (y + z)NH3
COONa
3.Apparatus and reagents




Apparatus
Constant temperature water bath, beaker,
graduated cylinder, stirring rod, electronic
balance.
Reagents
acrylamide (chemical pure), ammonium
persulfate (analytical pure), sodium
hydroxide (analytical pure)
4.Experimental procedures
1. The addition polymerization of acrylamide




(1) Weigh the mass of beaker and stirring rod with a electronic
balance (this mass would be used later). Then add 2g acrylamide
and 18mL water in the beaker to match a 10% acrylamide
solution.
(2) In the constant temperature water bath, heat the 10%
acrylamide solution to 60 ℃. Then add 15 drops of 10%
ammonium persulfate solution to trigger the addition
polymerization of acrylamide.
(3) In the process of addition polymerization, keep stirring slowly
and observe the changes of solution viscosity.
(4) Stop heating half an hour later, and the product is
polyacrylamide.
4.Experimental procedures

2. Polyacrylamide hydrolysis

(1) Weigh the obtained polyacrylamide, calculate the needed water to make
5% polyacrylamide solution.
(2) Add the required water in polyacrylamide solution, then stir it with a
stirring rod and observe the dissolution of the polymer.
(3)Weigh 20g 5% polyacrylamide solution ( the rest is control group) , add
2mL 10% sodium hydroxide, then place it in a boiling water bath and heat it to
above 90 ℃ for hydrolyzation.
(4)In the hydrolysis process, stir it slowly and observe the viscosity changes,
check the ammonia release (with wet pH paper of wide range).
(5)The beaker is removed from the boiling water bath half an hour later, and
the product is partially hydrolyzed polyacrylamide.
(6) Weigh the product mass, add the loss of evaporated water, and 5% partially
hydrolyzed polyacrylamide is made. Then compared the solution viscosity
before and after hydrolyzation.
(7)Pour the prepared polyacrylamide into the recycling bottle.






5.Experimental results processing

Explain all kinds of observed phenomena in
the experiment.
6.Questions

1. What is the impact of ammonium persulfate
amount on the molecular weight of synthesized
polyacrylamide?

2. Why the temperature is raised to 60 ℃during
the synthesis of polyacrylamide?

3. Analyze the factors that affect the molecular
weight of polyacrylamide.
EXPERIMENT 7
Determination of Polymer Molecular
Weight by Viscometric Method
Wang Zengbao
2011.4
1. Experimental purposes
Learn
and understand one method to determine
the polymer molecular weight .
2. Experimental principles
The polymer molecular weight is an average value owing
to the polydisperse molar mass distribution. The polymer
molecular weight determined by viscometric method is
called the Viscosity-average molecular weight ( M v).
Viscometric method includes multi-point method and onepoint method,we use one-point method.
2. Experimental principles
Because
  At    0

t
ln r  ln  ln
0
t0
and

  0
r 
SP 
0
0
Use these
formulas
to get Mv
  
  0 t  t0
SP 

0
t0
1
( SP  ln  r )
2c
[ ]  k M v
Mv

2. Experimental principles
In this experiment,
for measurement of
the viscosity of
polymer solution at
different
concentration, the
Ubbelohde-type
viscometer
illustrated in this Fig.
1, 2, 3—Branch pipe；
5, 8, 9－Glass bulb；
4, 6－Scale；
7－Capillary
We need record the time between the scale 4 and 6
3.Apparatus and reagents

Apparatus

The Ubbelohde-type viscometer, stopwatch,
suction bulb，graduated flask， Glass Constant
temperature water bath

Reagents

Polyacrylamide (PAM, industrial products),
Sodium nitrate (NaNO3, AR), Distilled water.
4.Experimental procedures






(1) Place the viscometer vertically in a thermostat bath maintained
at 30 ℃, and let it stand for about 15min to attain the specified
temperature.
(2) Add 15mL 1 mol/L sodium nitrate solution through branch pipe
3 into the glass bulb 9 .
Close tube 1 with a finger and pull the sample solution up to scale
4 by gentle suction from the top of tube 2, and stop the suction.
Remove the finger from tube 1 and immediately close the end of
tube 2.
Confirming that the meniscus of liquid column is cut off at the
scale 4, open the end of tube 2 to make the sample solution flow
down through the capillary tube 7.
Record the time required for the sample solution to fall from the
upper scale (scale 4) to the lower scale (scale 6) by stopwatch.
Repeat the above measurements at least 2 times and take the
average value .
4.Experimental procedures

(3) Cleaning of the Ubbelohde viscometer three
times with 0.01g/100mL polyacrylamide solution.

(4) Determine the polyacrylamide solution flow time
to fall from the scale 4 to the scale 6 using the
method mentioned above.
5.Experimental results processing

Calculation the
 SP 
  0 t  t0

0
t0
ln  r  ln

t
 ln
0
t0
Mv
1
   ( SP  ln r )
2c
[ ]  k M v

Mv
6.Questions

1. Summarize the experimental methods for
determining molecular weight and their scope of
application.

2. Why is NaNO3 added to determine of polymer
molecular weight by viscometric method? Are other
salts reasonable?

3. How to choose the concentration of polymer
solution in the multi-point method?