ASTM D5225-98(2003)
(Test Method)Standard Test Method for Measuring Solution Viscosity of Polymers with a Differential Viscometer
Standard Test Method for Measuring Solution Viscosity of Polymers with a Differential Viscometer
SIGNIFICANCE AND USE
Solution viscosity values for polymers are related to the average molecular size of that portion of the polymer which dissolves in the solvent.
SCOPE
1.1 This test method covers the determination of the solution viscosity of polymers using a differential or the modified differential viscometer. It is applicable to all polymers that dissolve completely without chemical reaction or degradation to form solutions that are stable with time and temperature. Results of the test are usually expressed as specific viscosity, intrinsic viscosity (limiting viscosity number), inherent viscosity (logarithmic viscosity number), or relative viscosity (viscosity ratio).
1.2 Since there is more than one type of viscometer available to measure a differential pressure, follow the manufacturers directions applicable to the equipment being used.
1.3 The solution viscosity values are comparable with those obtained using a glass capillary of Test Method D 2857. This test method differs from the glass capillary in that the solvent and the solution are compared at the same time that a test is run. With a glass capillary, each solution must be referenced back to the solvent run in the same capillary at the same temperature.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 8. Note 1
There is no ISO equivalent method.
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Standards Content (Sample)
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Designation:D 5225–98 (Reapproved 2003)
Standard Test Method for
Measuring Solution Viscosity of Polymers with a Differential
Viscometer
This standard is issued under the fixed designation D 5225; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope* D 2857 Test Method for Dilute Solution Viscosity of Poly-
mers
1.1 This test method covers the determination of the solu-
E 691 Practice for Conducting an Interlaboratory Study to
tion viscosity of polymers using a differential or the modified
Determine the Precision of a Test Method
differential viscometer. It is applicable to all polymers that
dissolve completely without chemical reaction or degradation
3. Terminology
to form solutions that are stable with time and temperature.
3.1 Definitions:
Results of the test are usually expressed as specific viscosity,
3.1.1 inherent viscosity—the ratio of the natural logarithm
intrinsic viscosity (limiting viscosity number), inherent viscos-
of the relative viscosity to the concentration. The IUPAC term
ity (logarithmic viscosity number), or relative viscosity (vis-
for inherent viscosity is logarithmic viscosity number.
cosity ratio).
3.1.2 intrinsic viscosity—limit of the reduced and inherent
1.2 Since there is more than one type of viscometer avail-
viscosities as the concentration of the polymeric solute ap-
able to measure a differential pressure, follow the manufactur-
proaches zero and represents the capacity of the polymer to
er’s directions applicable to the equipment being used.
increase viscosity. The IUPAC term for intrinsic viscosity is
1.3 The solution viscosity values are comparable with those
limiting viscosity number.
obtained using a glass capillary of Test Method D 2857. This
3.1.3 reduced viscosity—theratioofthespecificviscosityto
test method differs from the glass capillary in that the solvent
the concentration. Reduced viscosity is a measure of the
and the solution are compared at the same time that a test is
specific capacity of the polymer to increase the relative
run. With a glass capillary, each solution must be referenced
viscosity. The IUPAC term for reduced viscosity is viscosity
back to the solvent run in the same capillary at the same
number.
temperature.
3.1.4 relative viscosity—the ratio of the polymer solution
1.4 This standard does not purport to address all of the
pressure to the pressure of the solvent.
safety concerns, if any, associated with its use. It is the
3.1.5 specific viscosity—the relative viscosity minus one.
responsibility of the user of this standard to establish appro-
3.1.6 viscosity constant, K—baseline reading when solvent
priate safety and health practices and determine the applica-
is present in both capillaries.
bility of regulatory limitations prior to use. For specific hazard
statements, see Section 8.
4. Summary of Test Method
NOTE 1—There is no ISO equivalent method.
4.1 Differential Viscometer (Fig. 1):
4.1.1 The viscosity measurement with the differential vis-
2. Referenced Documents
cometer is based on a fluid analog of the Wheatstone Bridge.
2.1 ASTM Standards:
Pure solvent at constant inlet pressure P enters a balanced
i
D 1243 Test Method for Dilute Solution Viscosity of Vinyl
capillary network and flows through, producing a zero or
Chloride Polymers
baseline pressure on the differential pressure transducer. Solu-
tion is loaded into the sample reservoir A and then injected
onstream by means of the switching valve S . The differential
A
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
pressure begins to rise until it reaches a steady state value of
and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
DP proportional to the specific viscosity of the solution. The
Current edition approved November 1, 2003. Published December 2003.
differential pressure is monitored continuously on a strip chart
Originally approved in 1992. Last previous edition approved in 1998 as D 5225 -
recorder or computer, providing a baseline where DP is
98.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
measured. The equation relating DP to specific viscosity is:
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
4DP
Standards volume information, refer to the standard’s Document Summary page on
h 5 (1)
sp
the ASTM website. P 2 2DP
i
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 5225–98 (2003)
sample into capillary 2. The differential pressure P will
increase due to the higher viscosity of the sample solution.The
steady state value of P /P then yields the value of relative
2 1
viscosity of the sample.
P
Relative Viscosity 5 (3)
KP
4.2.1.3 Absolute viscosity of the sample may be calculated
from relative viscosity, RV, assuming the viscosity of the
solvent is known.
h~sample! 5 RV · h~solvent! (4)
5. Significance and Use
5.1 Solution viscosity values for polymers are related to the
average molecular size of that portion of the polymer which
dissolves in the solvent.
6. Apparatus
NOTE—
6.1 Differential Viscometer,ViscotekModel100-01viscom-
R,R,R,R = Matched SS Capillary Tubing
1 2 3 4
eter, or equivalent; or Relative Viscometer, Viscotek Model
A, B = Solution Holdup Reservoirs
Y-500, or equivalent,
S ,S = Switching Valve
A B
P= Solvent Inlet Pressure Transducer 6.2 Kit for conversion to GPC Detector,
i
DP = Differential Pressure Transducer
6.3 Computer, IBM PC or equivalent, with 640K RAM,
FIG. 1 Differential Viscometer
coprocessor, and graphics adapter,
6.4 PC Based Software, for data acquisition and processing.
6.5 PC interface with Data Translation Board and external
4.1.2 Derivation of the equation is in Annex A1.
signal box and cable,
4.2 Modified Differential Viscometer (Fig. 2):
6.6 Printer,
4.2.1 The modified differential viscometer has two stainless
6.7 Autosampler, Viscotek #100-06, or equivalent,
steel capillaries connected in series with a sample loading/
6.8 Glass Vial,25mL,
injection valve before the second capillary. Two differential
6.9 Screw Type Cap, open top, size 24-400,
pressure transducers, P and P , are connected in parallel
1 2
6.10 Septa, aluminum foil (household grade) or acceptable
across the capillaries. A pump continuously supplies solvent
substitute,
flow.The ratio of the pressures P and P is proportional to the
2 1
6.11 Balance, accurate to 0.0001 grams,
ratio of the viscosities of the fluid in capillary 2 to that in
6.12 Filter Funnel, and
capillary 1.
6.13 Filter medium, coarse filter paper or metal screen of
P h
2 2
140 mesh or finer.
5 K 5 K · Relative Viscosity (2)
P h
1 1
4.2.1.1 K, the viscosity constant, is obtained from the 7. Reagents and Materials
baseline reading when solvent is present in both capillaries, so
7.1 Polymer Sample.
h /h is unity.
2 1 7.2 Solvent.
4.2.1.2 With the valve in LOAD position, the sample is
7.3 Compressed Gas Cylinder of nitrogen or helium.
flushed through the sample loop by the syringe pump. A
baseline reading is established and recorded by the computer
8. Hazards
data acquisition system. When the valve is switched to the
8.1 Flammable solvents are to be used in a hood or a well
INJECT position, solvent flowing from capillary 1 pushes the
ventilated area.
8.2 Solvents are to be dated and to be used on a first-in
firs
...
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