ISO/FDIS 489

Plastics -- Determination of refractive index

Plastiques -- Détermination de l'indice de réfraction

General Information

• Status: Published
• ICS: 83.080.01 - Plastics in general
• Technical Committee: ISO/TC 61/SC 5 - Physical-chemical properties
• Drafting Committee: ISO/TC 61/SC 5/WG 11 - Analytical methods
• Current Stage: 5060 - Close of voting Proof returned by Secretariat
• Completion Date: 07-Jan-2022

RELATIONS

• Revised: ISO 489:1999 - Plastics -- Determination of refractive index
• Effective Date: 19-Dec-2020

Standards Content (sample)

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 489
ISO/TC 61/SC 5
Plastics — Determination of refractive
Secretariat: DIN
index
Voting begins on:
2021-11-12
Plastiques — Détermination de l'indice de réfraction
Voting terminates on:
2022-01-07
ISO/CEN PARALLEL PROCESSING
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 489:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. © ISO 2021
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ISO/FDIS 489:2021(E)
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All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

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© ISO 2021 – All rights reserved
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ISO/FDIS 489:2021(E)
Contents Page

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

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

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

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

4 Apparatus and materials ............................................................................................................................................................................1

4.1 Method A ...................................................................................................................................................................................................... 1

4.2 Method B ...................................................................................................................................................................................................... 2

5 Preparation of test specimens .............................................................................................................................................................. 3

5.1 Method A ...................................................................................................................................................................................................... 3

5.2 Method B ...................................................................................................................................................................................................... 3

5.3 Required number of specimens or measurements ................................................................................................ 3

6 Conditioning ............................................................................................................................................................................................................. 4

7 Procedure ....................................................................................................................................................................................................................4

7.1 Method A ...................................................................................................................................................................................................... 4

7.1.1 General ........................................................................................................................................................................................ 4

7.1.2 Transparent sheet ............................................................................................................................................................. 4

7.1.3 Film ................................................................................................................................................................................................. 6

7.1.4 Anisotropic material ....................................................................................................................................................... 6

7.1.5 Translucent, coloured and opaque material .............................................................................................. 7

7.2 Method B ...................................................................................................................................................................................................... 8

8 Precision ....................................................................................................................................................................................................................... 9

9 Test report .................................................................................................................................................................................................................. 9

Annex A (informative) Precision Data ............................................................................................................................................................10

Bibliography .............................................................................................................................................................................................................................12

iii
© ISO 2021 – All rights reserved
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ISO/FDIS 489:2021(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 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 third edition cancels and replaces the second edition (ISO 489:1999), which has been technically

revised.
The main changes compared to the previous edition are as follows:

— in the Scope, the description about the precision of the explanation of the method A and method B

has been deleted;
— normative references have been updated;
— the definition of the temperature control device of method A has been changed;
— the text of Clause 8, Precision, has been moved to Annex A;
— in Clause 9, the type of the immersing liquid used in method B has been added;
— the document has been editorial revised.

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.
© ISO 2021 – All rights reserved
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 489:2021(E)
Plastics — Determination of refractive index
1 Scope

This document specifies two test methods for determining the refractive index of plastics, namely:

— Method A: a refractometric method for measuring the refractive index of moulded parts, cast or

extruded sheet or film, by means of a refractometer. It is applicable not only to isotropic transparent,

translucent, coloured or opaque materials but also to anisotropic materials.

— Method B: an immersion method (making use of the Becke line phenomenon) for determining

the refractive index of powdered or granulated transparent materials by means of a microscope.

Monochromatic light, in general, is used to avoid dispersion effects.

NOTE The refractive index is a fundamental property which can be used for checking purity and

composition, for the identification of materials and for the design of optical parts. The change in refractive index

with temperature can give an indication of transition points of materials.
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 291, Plastics — Standard atmospheres for conditioning and testing
3 Terms and definitions
No terms and definitions are listed in this document.

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 https:// www .electropedia .org/
4 Apparatus and materials
4.1 Method A

4.1.1 Abbe refractometer, or any other refractometer that can be shown to give the same results,

reading precision to 0,001 and capable of measuring the refractive index in the range from 1 300 to

1 700. A temperature-controlling device (4.1.4) shall be provided for the specimens and prisms.

4.1.2 White or sodium lamp, used as a source of light.
4.1.3 Contacting liquid.

WARNING — The contacting liquid may present an environmental hazard during handling,

storage and disposal. It is the responsibility of the user of this document to verify its toxicity and

establish national and regional regulations for safe handling and disposal.
© ISO 2021 – All rights reserved
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ISO/FDIS 489:2021(E)

The contacting liquid shall have a refractive index higher than that of the material to be examined and

shall not soften, attack or dissolve the plastic material. The liquids listed in Table 1 may be used for the

respective plastic materials, but other liquids meeting these requirements may also be used.

Table 1 — Contacting liquids
Plastic material Contacting liquid
Cellulose derivatives Aniseed oil or 1-bromonaphthalene
Fluorine-containing polymers 1-Bromonaphthalene
Urea-formaldehyde Aniseed oil or 1-bromonaphthalene
Phenol-formaldehyde 1-Bromonaphthalene
Polyethylenes 1-Bromonaphthalene
Polyamides 1-Bromonaphthalene
Unsaturated polyester 1-Bromonaphthalene
Polyisobutylene Saturated aqueous solution of zinc chloride made slightly acid

Poly(methyl methacrylate) Saturated aqueous solution of zinc chloride made slightly acid or

1-bromonaphthalene
Polystyrene Saturated potassium mercury(II) iodide solution
Styrene-acrylonitrile copolymers 1-Bromonaphthalene
Vinyl resins (vinyl chloride copolymer or 1-Bromonaphthalene
plasticized PVC)
Poly(vinyl chloride) 1-Bromonaphthalene
Poly(ethylene terephthalate) Methylene iodide
Polycarbonate Methylene iodide

Diethylene glycol bis(allyl carbonate) (CR 39) Methyl salicylate, aniseed oil or 1-bromonaphthalene

Polyarylate Saturated aqueous solution of zinc chloride made slightly acid, meth-

ylene iodide or 1-bromonaphthalene
Polyetheretherketone Methylene iodide
Polypropylene 1-Bromonaphthalene

4.1.4 Temperature control system, capable of maintaining the temperature of the main prism, sub-

prism and specimen at (23 ± 0,5) °C.
4.2 Method B

4.2.1 Microscope, having a magnifying power of at least 200x, an objective giving approximately

20x of primary magnification and a substage condenser fitted with a centering illuminating-aperture

diaphragm capable of being stopped down to give a very narrow axial beam.

4.2.2 Monochromatic light, usually the sodium D line, having a wavelength of 589 nm, is used as the

light source for the microscope.
4.2.3 Immersion liquids, with different refractive indices.

WARNING — The contacting liquid may present an environmental hazard during handling,

storage and disposal. It is the responsibility of the user of this document to verify its toxicity and

establish national and regional regulations for safe handling and disposal.

The immersion liquids listed in Table 2 with known refractive indices can be used separately and also

as mixtures when different increments of accuracy are needed. The immersion liquids shall not soften,

attack, dissolve or swell the surface of the particles.
© ISO 2021 – All rights reserved
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ISO/FDIS 489:2021(E)
Table 2 — Immersion liquids
Immersion liquid Refractive index at 23 °C
n-Butyl carbonate 1 410
Tri-n-butyl citrate 1 444
n-Butyl phthalate 1 491
1-Bromonaphthalene 1 657
Diiodomethane (methylene iodide) 1 747
Aqueous solution of potassium mercury(II) iodide 1 419 to 1 733
Silico
...