EN ISO 1628-1:2024

Plastics - Determination of the viscosity of polymers in dilute solution using capillary viscometers - Part 1: General principles (ISO 1628-1:2024)

This document specifies the general conditions for the determination of the reduced viscosity, intrinsic viscosity and K‑value of organic polymers in dilute solution. It specifies the standard parameters that are applied to viscosity measurement.
This document is applicable to develop standards for measuring the viscosities in solution of individual types of polymer. It is also applicable to measure and report the viscosities of polymers in solution for which no separate standards exist.

Kunststoffe - Bestimmung der Viskosität von Polymeren in verdünnter Lösung durch ein Kapillarviskosimeter - Teil 1: Allgemeine Grundlagen (ISO 1628-1:2024)

Dieses Dokument legt die allgemeinen Grundlagen für die Bestimmung der reduzierten Viskosität, der intrinsischen Viskosität und des K-Wertes von organischen Polymeren in verdünnter Lösung fest. Es legt die bei Viskositätsmessungen angewendeten genormten Parameter fest.
Dieses Dokument ist für die Erarbeitung von Normen zur Messung der Viskositäten bestimmter Polymere in verdünnter Lösung anwendbar. Dieses Dokument ist auch zur Messung und Angabe der Viskositäten von Polymeren in verdünnter Lösung anwendbar, für die es keine spezielle Norm gibt.

Plastiques - Détermination de la viscosité des polymères en solution diluée à l'aide de viscosimètres à capillaires - Partie 1: Principes généraux (ISO 1628-1:2024)

Le présent document spécifie les conditions générales nécessaires pour déterminer la viscosité réduite, la viscosité intrinsèque et la valeur K des polymères organiques en solution diluée. Il spécifie les paramètres normalisés qui sont appliqués au mesurage de la viscosité.
Le présent document est applicable à l’élaboration des normes qui concernent le mesurage de la viscosité de différents types de polymères en solution. Il est également applicable pour mesurer et exprimer les viscosités des polymères en solution qui ne font l’objet d’aucune norme distincte.

Polimerni materiali - Določanje viskoznosti polimerov v razredčenih raztopinah s kapilarnimi viskozimetri - 1. del: Splošna načela (ISO 1628-1:2024)

Ta dokument določa splošne pogoje za določanje zmanjšane viskoznosti, lastne viskoznosti in vrednosti K polimerov v razredčenih raztopinah. Določa standardne parametre, ki se uporabljajo za merjenje viskoznosti.
Ta dokument se uporablja za pripravo standardov za merjenje viskoznosti v raztopinah posameznihvrst polimerov. Uporabiti ga je mogoče tudi za merjenje in sporočanje viskoznosti polimerov v raztopinah, za katere ne obstajajo posebni standardi.

General Information

• Status: Published
• Publication Date: 17-Dec-2024
• ICS: 83.080.01 - Plastics in general
• Technical Committee: CEN/TC 249 - Plastics
• Drafting Committee: CEN/TC 249 - Plastics
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 18-Dec-2024
• Completion Date: 18-Dec-2024
• Ref Project: SIST EN ISO 1628-1:2025 - Plastics - Determination of the viscosity of polymers in dilute solution using capillary viscometers - Part 1: General principles (ISO 1628-1:2024)

Relations

• Replaces: EN ISO 1628-1:2021 - Plastics - Determination of the viscosity of polymers in dilute solution using capillary viscometers - Part 1: General principles (ISO 1628-1:2021)
• Effective Date: 28-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
01-marec-2025
Polimerni materiali - Določanje viskoznosti polimerov v razredčenih raztopinah s
kapilarnimi viskozimetri - 1. del: Splošna načela (ISO 1628-1:2024)
Plastics - Determination of the viscosity of polymers in dilute solution using capillary
viscometers - Part 1: General principles (ISO 1628-1:2024)
Kunststoffe - Bestimmung der Viskosität von Polymeren in verdünnter Lösung durch ein
Kapillarviskosimeter - Teil 1: Allgemeine Grundlagen (ISO 1628-1:2024)
Plastiques - Détermination de la viscosité des polymères en solution diluée à l'aide de
viscosimètres à capillaires - Partie 1: Principes généraux (ISO 1628-1:2024)
Ta slovenski standard je istoveten z: EN ISO 1628-1:2024
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 1628-1
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2024
EUROPÄISCHE NORM
ICS 83.080.01 Supersedes EN ISO 1628-1:2021
English Version
Plastics - Determination of the viscosity of polymers in
dilute solution using capillary viscometers - Part 1:
General principles (ISO 1628-1:2024)
Plastiques - Détermination de la viscosité des Kunststoffe - Bestimmung der Viskosität von
polymères en solution diluée à l'aide de viscosimètres Polymeren in verdünnter Lösung durch ein
à capillaires - Partie 1: Principes généraux (ISO 1628- Kapillarviskosimeter - Teil 1: Allgemeine Grundlagen
1:2024) (ISO 1628-1:2024)
This European Standard was approved by CEN on 12 December 2024.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 1628-1:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 1628-1:2024) has been prepared by Technical Committee ISO/TC 61 "Plastics"
in collaboration with Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by SIS.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by June 2025, and conflicting national standards shall be
withdrawn at the latest by June 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 1628-1:2021.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 1628-1:2024 has been approved by CEN as EN ISO 1628-1:2024 without any
modification.
International
Standard
ISO 1628-1
Fifth edition
Plastics — Determination of
2024-12
the viscosity of polymers in
dilute solution using capillary
viscometers —
Part 1:
General principles
Plastiques — Détermination de la viscosité des polymères en
solution diluée à l'aide de viscosimètres à capillaires —
Partie 1: Principes généraux
Reference number
ISO 1628-1:2024(en) © ISO 2024

ISO 1628-1:2024(en)
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 1628-1:2024(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Terms related to any liquid.1
3.2 Terms related to polymer solutions .2
4 Principle . 3
4.1 General .3
4.2 Method A — Efflux time method . .4
4.3 Method B — Differential pressure method.4
5 Apparatus . 5
5.1 Efflux time method .5
5.2 Differential pressure method .8
6 Solutions . 9
6.1 Preparation .9
6.2 Concentration .9
7 Temperature of measurement . 10
8 Procedure .10
8.1 Efflux time method .10
8.1.1 General .10
8.1.2 Preparing and charging the viscometer .10
8.1.3 Efflux time measurement .10
8.2 Differential pressure method .11
8.2.1 General .11
8.2.2 Collection of viscosity ratio increment signal .11
9 Expression of results .12
9.1 Reduced viscosity and intrinsic viscosity . 12
9.2 K-value.14
10 Test report . 14
Annex A (informative) Efflux time method — Notes on sources of error .16
Annex B (informative) Differential pressure method — Notes on sources of error .20
Annex C (normative) Efflux time method — Cleaning of apparatus.22
Bibliography .23

iii
ISO 1628-1:2024(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical-
chemical properties, in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 249, Plastics, in accordance with the Agreement on technical cooperation between ISO
and CEN (Vienna Agreement).
This fifth edition cancels and replaces the fourth edition (ISO 1628-1:2021), which has been technically
revised.
The main changes are as follows:
— an introduction section has been added in relation to the new procedure;
— the calculation of K-value was moved to 9.2;
— an alternative procedure has been incorporated, the differential pressure method (see 4.3), based on
comparing the differential pressure in capillary tubing due to the flow of polymer solution and neat
solvent simultaneously.
A list of all parts in the ISO 1628 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
ISO 1628-1:2024(en)
Introduction
Two methods are described in this document to determine the viscosity of polymer solutions, the efflux time
method and the differential pressure method. The results of both methods are equivalent. Differences may
be found due to different conditions for the determination, such as concentration, solvent or shear rate.
The differential pressure method which has been incorporated in this document has the important advantage
for industry that it is more easily adapted to automation, leading to improved efficiency, higher throughput,
and enhanced safety for the operator. The new added method can help in the reduction of solvents use due to
the lower requirement for washing of the capillaries.
Another advantage of the new alternative differential pressure method is that it can be integrated within
existing polymer characterization workflows, as part of existing or new polymer analysis instrumental setups.

v
International Standard ISO 1628-1:2024(en)
Plastics — Determination of the viscosity of polymers in
dilute solution using capillary viscometers —
Part 1:
General principles
1 Scope
This document specifies the general conditions for the determination of the reduced viscosity, intrinsic
viscosity and K-value of organic polymers in dilute solution. It specifies the standard parameters that are
applied to viscosity measurement.
This document is applicable to develop standards for measuring the viscosities in solution of individual
types of polymer. It is also applicable to measure and report the viscosities of polymers in solution for which
no separate standards exist.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 80000-1, Quantities and units — Part 1: General
ISO 80000-4, Quantities and units — Part 4: Mechanics
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 80000-1, ISO 80000-4 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 Terms related to any liquid
3.1.1
viscosity
property of a fluid sheared between two parallel plates, one of which moves relative to the other in uniform
rectilinear motion in its own plane, defined by the Newton formula
τη= γ
where
ISO 1628-1:2024(en)
τ is the shear stress;
η
is the viscosity;

γ
dv
is the velocity gradient or rate of shear, given by where v is the velocity of one plane relative to
dz
the other and z the coordinate perpendicular to the two planes
Note 1 to entry: The units of viscosity are Pa⋅s.
Note 2 to entry: Viscosity is usually taken to mean “Newtonian viscosity”, in which case the ratio of shearing stress
to velocity gradient is constant. In non-Newtonian behaviour, which is the usual case with solutions of polymers
with high molar masses, the ratio varies with the shear rate. Such ratios are often called “apparent viscosities” at the
corresponding shear rate.
3.1.2
viscosity/density ratio
kinematic viscosity
v
ratio defined by the formula
η
v=
ρ
where ρ is the density of the fluid at the temperature at which the viscosity is measured
2 −1
Note 1 to entry: The units of kinematic viscosity are m ⋅s .
3.2 Terms related to polymer solutions
3.2.1
relative viscosity
viscosity ratio
η
r
ratio of the viscosity of the polymer solution (of stated concentration) η and the viscosity of the solvent η , at
the same temperature
η
η =
r
η
Note 1 to entry: The ratio has no dimensions.
3.2.2
relative viscosity increment
viscosity ratio increment and specific viscosity
η
sp
viscosity ratio minus one
ηη−
 η 
η = −=1
 
sp
η η
 0  0
Note 1 to entry: The increment has no dimensions.
3.2.3
reduced viscosity
viscosity number
I
ISO 1628-1:2024(en)
ratio of the relative viscosity increment to the polymer concentration c in the solution
ηη−
Ι =
η c
Note 1 to entry: The units of reduced viscosity are m /kg.
3 3
Note 2 to entry: The reduced viscosity is usually determined at low concentration (less than 5 kg/m , i.e. 0,005 g/cm ),
except in the case of polymers of low molar mass, for which higher concentrations can be necessary.
3.2.4
inherent viscosity
logarithmic viscosity number
η
inh
ratio of the natural logarithm of the viscosity ratio to the polymer concentration in the solution
 
η
ln
 
η
 0 
η =
inh
c
Note 1 to entry: The dimensions and units are the same as those given in 3.2.3.
Note 2 to entry: The inherent viscosity is usually determined at low concentration (less than 5 kg/m , i.e. 0,005 g/
cm ), except in the case of polymers of low molar mass, for which higher concentrations can be necessary.
3.2.5
intrinsic viscosity
limiting viscosity number
η
limiting value of the reduced viscosity or of the inherent viscosity (3.2.4) at infinite dilution
ηη− 
η = lim
[]
 
c→0 η c
 
 
η
ln
 
η
 
[]η = lim
c→0 c
Note 1 to entry: The dimensions and units are the same as those given in 3.2.3.
Note 2 to entry: The effect of the shear rate on the functions defined in 3.2.1 to 3.2.5 has been neglected, since this
effect is usually negligible for values of the reduced viscosity, inherent viscosity and intrinsic viscosity less than
3 3
0,5 m /kg, i.e. 500 cm /g. Strictly speaking, all these functions can be defined at the limiting (preferably infinitely
small) value of the shear rate.
3.2.6
K-value
empirical parameter related to the relative viscosity and concentration used to estimate the viscosity
average of the molecular mass of polymers
Note 1 to entry: For constant measurement parameters such as type of solvent, concentration and temperature, the
K-value depends only on the viscosity average of the molecular mass distribution.
4 Principle
4.1 General
The data needed for the evaluation of the functions defined in 3.2 are obtained comparing viscosity
measurements of a polymer solution and the solvent.

ISO 1628-1:2024(en)
4.2 Method A — Efflux time method
The data are obtained by means of a capillary-tube viscometer. The efflux times of a given volume of solvent
t and of solution t are measured at fixed temperature and atmospheric-pressure conditions in the same
viscometer. The efflux time of a liquid is related to its viscosity by the Poiseuille-Hagenbach-Couette formula
as shown in Formula (1):
η  A 
vC== t − (1)
 
ρ
 
t
where
v is the viscosity/density ratio;
C is a constant of the viscometer;
A is a parameter of the kinetic-energy correction;
ρ is the density of the liquid;
η is the viscosity of the liquid;
t is the efflux time.
 A 
For the purposes of this document, the kinetic energy correction shall be regarded as negligible when
 
 
t
it is less than 3 % of the viscosity of the solvent. Hence, Formula (1) can be reduced to Formula (2):
η
vC== t (2)
ρ
Moreover, if the solution concentrations are limited so that the solvent density ρ and that of the solution ρ
η t
differ by less than 0,5 %, the viscosity ratio will be given by the so-called “efflux time ratio” .
η t
0 0
The need for these constraints, and the consequences of not observing them, is described in Annex A.
4.3 Method B — Differential pressure method
The data are obtained by means of a 2-capillary relative viscometer. The differential pressure across each of
the 2 capillaries connected in series, one of them receiving the solvent ∆p , the other receiving the polymer
solution ∆p, are measured at a fixed temperature while applying a forced flow through them.
The differential pressure across a capillary tubing is related to the viscosity of the flowing liquid under
laminar flow regime, by the Poiseuille formula as shown in Formula (3):
8ql
v
Δp= η (3)
πr
where
∆p is the differential pressure in a capillary tubing;
q is the liquid flow rate;
v
l is the capillary tubing length;
r is the capillary tubing radius;
η is the viscosity of the liquid;

ISO 1628-1:2024(en)
As in a 2-capillaries serial configuration viscometer (see 5.2) the same flow rate q is maintained for the
v
η Δp
solvent and the polymer solution, the viscosity ratio is proportional to the pressure ratio . By
η Δp
0 0
η
introducing the instrumental constant K the viscosity ratio can be calculated from the pressure ratio
v
η
as seen in Formula (4) and Formula (5):
η Δp
=⋅K (4)
v
η Δp
with
rl
K = (5)
v
rl
where
l is the polymer solution capillary tubing length;
r is the polymer solution capillary tubing radius;
l is the solvent capillary tubing length;
r is the solvent capillary tubing radius.
The instrumental constant K can easily be measured by flowing solvent through both capillaries given that
v
η
the viscosity ratio is 1,0 for solvent, and therefore solving in Formula (4):
η
Δp
K =
v
Δp
Possible sources of errors for this method are described in Annex B.
5 Apparatus
5.1 Efflux time method
5.1.1 Capillary viscometer, of the suspended-level Ubbelohde type
The use of a viscometer having the dimensions given in Figure 1 or Figure 2 is strongly recommended.
Furthermore, it is strongly recommended that the size of the viscometer be chosen from among those listed
in Table 1. The choice is determined by the viscosity/density ratio of the solvent at the temperature of the
measurement, as indicated in Table 1. The next-smaller viscometer may also be used.
Other types of viscometer listed in ISO 3105 may be used, provided they give results equivalent to those
given by the particular size of Ubbelohde viscometer chosen on the basis of the criteria specified in the
preceding paragraph. In cases of dispute, an Ubbelohde viscometer shall be used.
With automated apparatuses, fitted with special timing devices, equivalent results with larger sizes of
capillaries than those listed for the appropriate solvent viscosity/density ratio in Table 1 can be obtained.
Some modified viscometer excluding parts P and L can be used, and the measuring part of the viscometer
meets the recommendations of the Table 1.
5.1.2 Viscometer holder, suitable to hold the viscometer firmly in the thermostatic bath (5.1.3) in the
vertical position.
ISO 1628-1:2024(en)
Dimensions in millimetres
Key
A lower reservoir 26 mm internal diameter L mounting tube 11 mm internal diameter
B suspended level bulb M lower vent tube 6 mm internal diameter
C timing bulb N upper vent tube 7 mm internal diameter
D upper reservoir P connecting tube
E and F timing marks R working capillary
G and H filling marks
Figure 1 — Ubbelohde viscometer

ISO 1628-1:2024(en)
5.1.3 Thermostatic bath, transparent liquid or vapour bath of a size such that, during the measurement,
all sections containing test liquid are at least 20 mm below the surface of the bath medium and at least
20 mm away from all boundaries of the bath tank.
The temperature control shall be such that, within the range 25 °C to 100 °C, the temperature of the bath
does not vary from the specified temperature by more than 0,05 K over the length of the viscometer, or
between the viscometers if several determinations are carried out simultaneously.
At temperatures higher than 100 °C, the tolerance shall be ±0,2 K.
Dimensions in millimetres
NOTE For key, see Figure 1.
Figure 2 — DIN Ubbelohde viscometer

ISO 1628-1:2024(en)
5.1.4 Temperature-measuring device, thermometer, reading to 0,02 °C in the range in which it will be
used and in a known state of calibration, is suitable.
5.1.5 Timing device. Any timing device may be used providing that it can be read to 0,1 s and that its
speed is constant to 0,1 % over 15 min.
Table 1 — Ubbelohde viscometers recommended for the determination of the dilute-solution
viscosity of polymers
Viscosity/density
ratio of solvent at Nominal viscom- Ubbelohde conforming to DIN Ubbelohde conforming to
temperature of eter constant ISO 3105 ISO 3105
measurement
Inside diameter Inside diameter
Size No. Size No.
a a
of tube R of tube R
2 −1 2 −2
mm ⋅s mm ⋅s mm mm
0,15 to 0,30 0,001 0 0,24 0 0,36
0,31 to 0,50 0,003 0C 0,36 0c 0,47
0,51 to 0,75 0,005 0B 0,46 0a 0,53
0,76 to 1,50 0,01 1 0,58 I 0,63
1,51 to 2,50 0,03 1C 0,77 Ic 0,84
2,51 to 5,00 0,05 1B 0,88 Ia 0,95
5,01 to 15,00 0,1 2 1,03 II 1,13
a
The tolerance of the inside diameter of tube R is ±2 %.
5.2 Differential pressure method
A schematic diagram of a relative viscometer used in this method is depicted in Figure 3, indicating the
relevant components. It is strongly recommended to use automated instruments capable of injecting
polymer solutions into the measurement/polymer solution capillary while maintaining a constant flow of
solvent (q ) through the system.
v
Key
A solvent reservoir F reference/solvent capillary
B solvent delivery system G measurement/polymer solution capillary
C polymer solution injection system q liquid flow rate
v
D polymer solution ∆p differential pressure across the reference capillary
E waste reservoir ∆p differential pressure across the measurement capillary
Figure 3 — 2-capillary relative viscometer
The solvent delivery system (B) may be a positive displacement pump, syringe pump or similar capable
of delivering solvent
...