Plastics - Polyamides - Determination of viscosity number (ISO 307:2019)

This document specifies a method for the determination of the viscosity number of dilute solutions of polyamides in certain specified solvents.
The method is applicable to the polyamides designated PA 46, PA 6, PA 66, PA 69, PA 610, PA 612, PA 11, PA 12, PA 6T/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 6I/6T/66 and PA MXD6 as defined in ISO 16396-1, as well as to copolyamides, compounds of polyamides and other polyamides that are soluble in one of the specified solvents under the specified conditions.
The method is not applicable to polyamides produced by anionic polymerization of lactams or produced with cross-linking agents; such polyamides are normally insoluble in the specified solvents.
The viscosity number is determined by the general procedure specified in ISO 1628‑1, observing the particular conditions specified in this document.

Kunststoffe - Polyamide - Bestimmung der Viskositätszahl (ISO 307:2019)

Dieses Dokument legt ein Verfahren zur Bestimmung der Viskositätszahl von verdünnten Polyamidlösungen in bestimmten, festgelegten Lösemitteln fest.
Das Verfahren ist auf Polyamide mit den Bezeichnungen PA 46, PA 6, PA 66, PA 69, PA 610, PA 612, PA 11, PA 12, PA 6T/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 6I/6T/66 und PA MXD6, wie in ISO 16396 1 definiert, und Copolyamide, Polyamid Mischungen und sonstige Polyamide anwendbar, die unter den fest-gelegten Bedingungen in einem der festgelegten Lösemittel löslich sind.
Das Verfahren ist nicht auf Polyamide anwendbar, die durch anionische Polymerisation von Laktamen oder mit Vernetzungsmitteln hergestellt wurden; derartige Polyamide sind normalerweise in den festgelegten Lösemitteln unlöslich.
Die Viskositätszahl wird nach dem in ISO 1628 1 festgelegten allgemeinen Verfahren unter Beachtung der in diesem Dokument festgelegten besonderen Bedingungen bestimmt.

Plastiques - Polyamides - Détermination de l'indice de viscosité (ISO 307:2019)

Le présent document spécifie une méthode pour la détermination de l'indice de viscosité de solutions diluées de polyamides dans certains solvants spécifiés.
La méthode est applicable aux polyamides désignés PA 46, PA 6, PA 66, PA 69, PA 610, PA 612, PA 11, PA 12, PA 6T/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 6I/6T/66 et PA MXD6, tels que définis dans I'ISO 16396‑1, ainsi qu'aux copolyamides, aux composés polyamides et aux autres polyamides solubles dans l'un des solvants spécifiés dans les conditions spécifiées.
La méthode n'est pas applicable aux polyamides obtenus par polymérisation anionique des lactames ou produits avec des agents de réticulation, de tels polyamides étant normalement insolubles dans les solvants spécifiés.
L'indice de viscosité est déterminé selon le mode opératoire général spécifié dans l'ISO 1628‑1, en tenant compte des conditions particulières spécifiées dans le présent document.

Polimerni materiali - Poliamidi - Določanje števila viskoznosti (ISO 307:2019)

Ta dokument določa metodo za določanje števila viskoznosti razredčenih raztopin poliamidov v nekaterih določenih topilih.
Metoda se uporablja za poliamide z oznakami PA 46, PA 6, PA 66, PA 69, PA 610, PA 612, PA 11, PA 12, PA 6T/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 6I/6T/66 in PA MXD6, kot je opredeljeno v standardu ISO 16396-1,
kot tudi za kopoliamide, spojine poliamidov in druge poliamide, ki so pod določenimi pogoji topni v enem od določenih topil.
Metoda se ne uporablja za poliamide, ki nastanejo z anionsko polimerizacijo laktamov ali so proizvedeni s sredstvi za prečno povezovanje; taki poliamidi so običajno netopni v določenih topilih. Vrednost viskoznosti je določena s splošnim postopkom, opredeljenim v standardu ISO 1628-1, ob upoštevanju posebnih pogojev, opredeljenih v tem dokumentu.

General Information

Status
Published
Publication Date
28-May-2019
Technical Committee
Drafting Committee
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
29-May-2019
Completion Date
29-May-2019

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SLOVENSKI STANDARD
SIST EN ISO 307:2019
01-september-2019
Nadomešča:
SIST EN ISO 307:2007
SIST EN ISO 307:2007/A1:2014
Polimerni materiali - Poliamidi - Določanje števila viskoznosti (ISO 307:2019)
Plastics - Polyamides - Determination of viscosity number (ISO 307:2019)
Kunststoffe - Polyamide - Bestimmung der Viskositätszahl (ISO 307:2019)
Plastiques - Polyamides - Détermination de l'indice de viscosité (ISO 307:2019)
Ta slovenski standard je istoveten z: EN ISO 307:2019
ICS:
83.080.20 Plastomeri Thermoplastic materials
SIST EN ISO 307:2019 de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 307:2019
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SIST EN ISO 307:2019
EN ISO 307
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2019
EUROPÄISCHE NORM
ICS 83.080.20 Supersedes EN ISO 307:2007
English Version
Plastics - Polyamides - Determination of viscosity number
(ISO 307:2019)

Plastiques - Polyamides - Détermination de l'indice de Kunststoffe - Polyamide - Bestimmung der

viscosité (ISO 307:2019) Viskositätszahl (ISO 307:2019)
This European Standard was approved by CEN on 19 March 2019.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey 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

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 307:2019 E

worldwide for CEN national Members.
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SIST EN ISO 307:2019
EN ISO 307:2019 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 307:2019
EN ISO 307:2019 (E)
European foreword

This document (EN ISO 307:2019) 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 NBN.

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 November 2019, and conflicting national standards

shall be withdrawn at the latest by November 2019.

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 307:2007.

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, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
Endorsement notice

The text of ISO 307:2019 has been approved by CEN as EN ISO 307:2019 without any modification.

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SIST EN ISO 307:2019
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SIST EN ISO 307:2019
INTERNATIONAL ISO
STANDARD 307
Sixth edition
2019-04
Plastics — Polyamides —
Determination of viscosity number
Plastiques — Polyamides — Détermination de l'indice de viscosité
Reference number
ISO 307:2019(E)
ISO 2019
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SIST EN ISO 307:2019
ISO 307:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

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: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
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SIST EN ISO 307:2019
ISO 307:2019(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 3

5 Reagents and materials ................................................................................................................................................................................. 3

5.1 Solvents and reagents ....................................................................................................................................................................... 3

5.2 Cleaning liquids ...................................................................................................................................................................................... 4

6 Apparatus ..................................................................................................................................................................................................................... 4

7 Preparation of test samples ...................................................................................................................................................................... 5

7.1 General ........................................................................................................................................................................................................... 5

7.2 Samples containing less than 98 % (by mass) polyamide ................................................................................. 6

8 Calculation of test portion .......................................................................................................................................................................... 6

9 Selection of solvent ............................................................................................................................................................................................ 6

10 Procedure..................................................................................................................................................................................................................... 7

10.1 Cleaning of the viscometer ........................................................................................................................................................... 7

10.2 Preparation of test solution ......................................................................................................................................................... 7

10.2.1 General...................................................................................................................................................................................... 7

10.2.2 Volumetric method ........................................................................................................................................................ 8

10.2.3 Volumetric method, in exact relation to the polymer content .................................................. 8

10.2.4 Gravimetric method, in exact relation to the polymer content ................................................ 8

10.3 Measurement of flow times ......................................................................................................................................................... 9

11 Expression of results .....................................................................................................................................................................................10

12 Repeatability and reproducibility ...................................................................................................................................................11

13 Relationship between the viscosity number determined in 96 % (by mass) sulfuric

acid solution and the viscosity determined in various solvents ......................................................................11

14 Test report ................................................................................................................................................................................................................11

Annex A (informative) Determination of the concentration of commercial sulfuric

acid(95 % to 98 %) and adjustment to 96 % by titration.......................................................................................13

Annex B (informative) Determination of the concentration of sulfuric acid (95 % to 98 %)

and adjustment to 96 % by flow time measurement in a small capillary viscometer ..............16

Annex C (informative) Determination of the concentration of commercial formic acid and

adjustment to 90 % by titration ........................................................................................................................................................18

Annex D (informative) Determination of the concentration of commercial formic acid and

adjustment to 90 % by density measurement ....................................................................................................................20

Annex E (informative) Relationship between the viscosity number determined in 96 % (by

mass) sulfuric acid solution and the viscosity determined in various solvents ..............................23

Bibliography .............................................................................................................................................................................................................................35

© ISO 2019 – All rights reserved iii
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SIST EN ISO 307:2019
ISO 307:2019(E)
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).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on 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 the following

URL: www .iso .org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 9,

Thermoplastic materials.

This sixth edition cancels and replaces the fifth edition (ISO 307:2007), which has been technically

revised to update Clause 9. It also incorporates the Amendment ISO 307:2007/Amd.1:2013.

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 2019 – All rights reserved
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SIST EN ISO 307:2019
ISO 307:2019(E)
Introduction

This document specifies a method for the determination of the viscosity number of dilute solutions of

polyamides in certain specified solvents. The determination of the viscosity number of a polyamide

provides a value that depends on the molecular mass of the polymer, but does not strictly correlate with

the molecular mass.

Additives such as flame-retardants and modifiers often interfere with the viscosity measurement and

may have an increasing effect on the viscosity number in one solvent and a decreasing effect in another

solvent. The extent of the effect depends among others on the additive, the quantity of the additive, the

presence of other additives and reactions.

The viscosity number of a polyamide sample containing additives that interfere with the viscosity

measurement, measured in a specific solvent, represents a specific viscosity number for the polyamide

under investigation and the actual measurement conditions. The measured viscosity number cannot, in

principle, be converted from one solvent to another and is only suitable for intra-product comparison.

The viscosity number of pure polyamides or polyamides containing additives that do not interfere with

the viscosity measurement can be converted from one solvent to another by a general relationship for

that type of polyamide.

Polyamide test samples for the determination of the viscosity number are intended to be completely

soluble in the solvents mentioned. Additives contained in them, like glass and carbon fibres, are to be

separated from the solution.

As it is not possible to distinguish between extractables such as caprolactam, its oligomers and other

extractable additives, these are considered as an essential part of the sample and therefore included in

the sample mass.

The test method is applicable for production control and intra-product comparison even if the polyamide

contains additives that do interfere with the viscosity measurement. However, it should be realised that

deviations of the viscosity number can be caused by either the polyamide itself, effects caused by the

additives present, or a combination of these.

The interference of additives with the viscosity determination can be checked by comparing the

viscosity results of dry blend mixtures and regular production samples at several concentrations of the

additive under investigation and in the solvents concerned. It should be noted that the other additives

present also could influence the viscosity result.

The repeatability and reproducibility of the test method are strongly influenced by the correctness of

the solvent concentration, the use of the Hagenbach correction if applicable and the temperature of the

solvent on diluting the sample solution.

In this document, two specific viscometers are recommended. Furthermore, other types of viscometers

listed in ISO 3105 may also be used, provided that the results are demonstrated to be equivalent to

those measured with the recommended viscometers. It is to be expected that in the next revision the

use of the other types of viscometers will be excluded.
© ISO 2019 – All rights reserved v
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SIST EN ISO 307:2019
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SIST EN ISO 307:2019
INTERNATIONAL STANDARD ISO 307:2019(E)
Plastics — Polyamides — Determination of viscosity number
1 Scope

This document specifies a method for the determination of the viscosity number of dilute solutions of

polyamides in certain specified solvents.

The method is applicable to the polyamides designated PA 46, PA 6, PA 66, PA 69, PA 610, PA 612, PA 11,

PA 12, PA 6T/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 6I/6T/66 and PA MXD6 as defined in ISO 16396-1,

as well as to copolyamides, compounds of polyamides and other polyamides that are soluble in one of

the specified solvents under the specified conditions.

The method is not applicable to polyamides produced by anionic polymerization of lactams or produced

with cross-linking agents; such polyamides are normally insoluble in the specified solvents.

The viscosity number is determined by the general procedure specified in ISO 1628-1, observing the

particular conditions specified in this document.
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 1042, Laboratory glassware — One‑mark volumetric flasks

ISO 1628-1, Plastics — Determination of the viscosity of polymers in dilute solution using capillary

viscometers — Part 1: General principles

ISO 3105, Glass capillary kinematic viscometers — Specifications and operating instructions

ISO 3451-4, Plastics — Determination of ash — Part 4: Polyamides
ISO 15512, Plastics — Determination of water content

ISO 16396-1, Plastics — Polyamide (PA) moulding and extrusion materials — Part 1: Designation system,

marking of products and basis for specifications
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 1628-1 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
viscosity number

value calculated by the following formula for flow times long enough so that no kinetic

energy correction need be applied:
 
η 1
VN=−1 ×
 
η c
 
© ISO 2019 – All rights reserved 1
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SIST EN ISO 307:2019
ISO 307:2019(E)
where

η is the viscosity of a solution of the polymer in a specified solvent, in Pa/ s or N/m ·s;

η is the viscosity of the solvent, expressed in the same units as η;
is the relative viscosity of a solution of the polymer in a specified solvent;
c is the concentration, in g/ml, of the polymer in the solution;
VN is the viscosity number, expressed in ml/g

Note 1 to entry: The formula is applicable to the viscometers of the suspended level Ubbelohde type, complying

with the requirements of ISO 3105.

Note 2 to entry: For a particular viscometer used and with substantially equal densities of the solvent and

solution, the viscosity ratio is given by the flow time ratio for the solution concentration:

where is the relative viscosity of a solution of the polymer in a specified solvent.

Note 3 to entry: As mentioned in ISO 3105, in case of flow times below 200 s and 60 s, for type 1 and type 2

Ubbelohde viscometers respectively, a correction for kinetic correction has to be applied: the so-called Hagenbach

correction. For other types of viscometers, the kinetic energy correction has to be applied if the correction is

≥0,15 %.

Note 4 to entry: The flow time of a liquid is related to its viscosity by the formula:

η  A 
vC== ×−t
 
t 
where

η is the viscosity of a solution of the polymer in a specified solvent, in Pa/ s or N/m ⋅s;

v is the viscosity/density ratio, in metres squared per second;
ρ is the density of the liquid, in kilograms per cubic metre;
C is the constant of the viscometer, in metres squared per second squared;
t is the flow time, in seconds;
A is the parameter of the kinetic correction in metres squared seconds.

Note 5 to entry: For a particular viscometer used, with substantially equal densities of the solvent and solution

and a given kinetic factor, the viscosity ratio

is given by the flow time ratio for the solution concentration in this document, each flow time reduced with the

so-called Hagenbach correction (in seconds) given by the manufacturer for the viscometer as a function of the

flow time.
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SIST EN ISO 307:2019
ISO 307:2019(E)
4 Principle

The times of flow of a solvent and a solution of the polyamide at a concentration of 0,005 g/ml in the

solvent are measured at 25 °C, the same viscometer being used for both measurements. The viscosity

number is calculated from these measurements and from the known concentration of the solution.

5 Reagents and materials
5.1 Solvents and reagents

Only reagents of recognised analytical grade and only distilled water or water of equivalent purity shall

be used.

SAFETY STATEMENT — Persons using this document should be familiar with laboratory practice.

This document does not purport to address all of the safety concerns associated with its use.

Some chemicals, for example 1,1,2,2-tetrachloroethane, are prohibited in some countries. It is

the responsibility of the user to establish appropriate safety and health practices and to ensure

compliance with any regulatory requirements.

WARNING — Avoid contact with the skin and inhalation of any vapours of the solvents and

cleaning liquids.
5.1.1 Sulfuric acid, 96,00 % ± 0,20 % (by mass) solution.

For the determination of the concentration of commercial sulfuric acid (95 % to 98 %) and adjustment

to 96,00 %, is referred to Annexes A and B.
5.1.2 Formic acid, 90,00 % ± 0,15 % (by mass) solution.

The solvent shall be stored in a brown glass bottle. Its concentration shall be checked at least every

2 weeks. It shall not contain more than 0,2 % acetic acid or methyl formate.

For the determination of the concentration of commercial formic acid (90 %) and adjustment to

90,00 % ± 0,15 %, is referred to Annexes A and B.
5.1.3 m-Cresol, meeting the following specifications:
— appearance: clear and colourless;
— m-cresol content: 99 % (by mass) min.;
— o-cresol content: 0,3 % (by mass) max.;
— water content: 0,13 % (by mass) max.

m-Cresol of the required purity may be obtained by distillation of chemically pure m-cresol, preferably

in vacuum. If distillation is used, nitrogen shall be used for pressure compensation to avoid oxidation.

Its purity may be checked by gas chromatography. The solvent shall be stored in a brown glass bottle.

5.1.4 Phenol, 99 % (by mass) min.
5.1.5 1,1,2,2-tetrachloroethane, 99,5 % (by mass) min.
5.1.6 Phenol/1,1,2,2-tetrachloroethane.

Weigh out 6 parts by mass of phenol (5.1.4) and dissolve in 4 parts by mass of 1,1,2,2-tetrachloroethane

(5.1.5). Work to an accuracy of 1 % or better in the weighings. Stir the mixture in its original container

at 23 °C to prevent crystallization.
© ISO 2019 – All rights reserved 3
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SIST EN ISO 307:2019
ISO 307:2019(E)
5.1.7 Orthophosphoric acid, 85 % (by mass), density 1,71 g/ml.
5.1.8 m-Cresol/phosphoric acid.

Transfer 50 ml of m-cresol (5.1.3) into a weighing flask (6.4) and add with a glass pipette (6.5) 0,14 ml

of orthophosphoric acid (5.1.7). Close the flask and stir with a magnetic stirrer for 30 min at 100 °C.

Add the solution to approximately 800 ml of m-cresol in a volumetric flask while continuously stirring.

Rinse the weighing flask several times with m-cresol and add this to the m-cresol solution. Remove the

magnetic stirrer and dilute to the mark. Stir the solution for 30 min.
5.2 Cleaning liquids

5.2.1 Chromic acid solution, prepared by mixing equal volumes of sulfuric acid (96 %, ρ = 1,84 g/

ml, industrial quality) and a saturated solution of potassium dichromate (99,5 %, industrial quality). If

required, the chromic acid solution may be replaced by other equally effective cleaning liquids.

5.2.2 Acetone (99,5 %, industrial quality), or any water-soluble low-boiling-point solvent (industrial

quality).
6 Apparatus
6.1 Vacuum drying cabinet, with pressure less than 100 kPa.
6.2 Balance, accurate to 0,1 mg.

6.3 Volumetric flask, of capacity 50 ml or 100 ml, complying with the requirements of ISO 1042, fitted

with a ground-glass stopper.
6.4 Weighing flask, 100 ml, fitted with a ground-glass stopper.
6.5 Pipette, 0,2 ml, readable to 0,01 ml.
6.6 Shaking apparatus or magnetic stirrer.

6.7 Sintered‑glass filter, with a pore size between 40 μm and 100 μm (grade P 100), or stainless-steel

sieve, with apertures of about 0,075 mm .

6.8 Viscometer, of the suspended-level Ubbelohde type, complying with the requirements of ISO 3105.

The essential dimensions of the viscometer are shown in Figure 1. For use with the formic acid solution

(5.1.2), the inside diameter of the capillary shall be 0,58 mm ± 2 % (complying with the requirements

of size No. 1 of ISO 3105). For use with the sulfuric acid solution (5.1.1) or m-cresol (5.1.3), the inside

diameter of the capillary shall be 1,03 mm ± 2 % (complying with the requirements of size No. 2 of

ISO 3105).

Other types of viscometer listed in ISO 3105 may be used, provided that the results are demonstrated

to be equivalent to those of the Ubbelohde viscometers specified above. In cases of dispute, the

recommended viscometer shall be used.
ISO 1628-1 shall be followed on selecting other type(s) of viscometer.

In this document, the No. 1 and No. 2 Ubbelohde viscometers according to ISO 3105 are recommended.

It is to be expected that at the next 5 year revision only these two viscometers will be allowed.

4 © ISO 2019 – All rights reserved
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SIST EN ISO 307:2019
ISO 307:2019(E)
Dimensions in millimetres
Key
1 graduation marks for a volume of 4 ml ± 0,2 ml

2 capillary tube of diameter 0,58 mm ± 2 % for formic acid; 1,03 mm ± 2 % for sulfuric acid and m-cresol

3 filling marks
Figure 1 — Ubbelohde viscometer

6.9 Thermometer, a liquid-in-glass, “total immersion” thermometer, reading to 0,05 °C in the range

to be used and in a known state of calibration, is suitable. Other thermometric devices of at least equal

precision may be used.

6.10 Thermostatic bath, capable of being maintained and controlled at 25,00 °C ± 0,05 °C.

6.11 Time device, for example a stop-watch, accurate to 0,1 s.
6.12 Centrifuge.
7 Preparation of test samples
7.1 General

Polyamide test samples for the determination of the viscosity number shall be soluble in the solvents

mentioned, except for additives present, such as reinforcement or fillers.

The sample should contain less than 0,28 % moisture. If it contains more than 0,28 % moisture the

sample should be dried. Generally, drying at 70 °C in a vacuum for 4 h to 6 h is adequate.

NOTE The dissolution time of some samples might be too long for adequate production control. In these cases,

the material can be ground in order to shorten the dissolution time, provided that the results are demonstrated

to be equivalent.
© ISO 2019 – All rights
...

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