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UDC 678.01 Ref. No.: lSO/ R 173 - I861 (E)
IS0
I NT ERN AT1 ON AL O RG AN IZATl ON FOR STA N DA RD I ZATl O N
IS0 RECOMMENDATION
R 173
P LAST I CS
DETERMINATION OF THE PERCENTAGE OF STYRENE
IN POLYSTYRENE WITH WIJS SOLUTION
1st EDITION
February 1961
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies, Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian, Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 173, Determination of the Percentage of Styrene in Poly-
styrene with Wijs Solution, was drawn up by Technical Committee ISO/TC 61, Plastics, the
Secretariat of which is held by the American Standards Association, Incorporated (ASA).
Work on this matter which the Technical Committee had begun since 1954, came to
an end in 1956, with the adoption of a proposal as a Draft IS0 Recommendation.
On 28 November 1958, the Draft IS0 Recommendation (No. 188) was distributed to
all the IS0 Member Bodies and was approved, subject to some editorial amendments, by
the following Member Bodies :
Australia Hungary Romania
India Spain
Austria
Belgium Israel Sweden
Bulgaria Italy Switzerland
Burma Japan Turkey
Netherlands United Kingdom
Czechoslovakia
France Poland U.S.A.
Germany Portugal U.S.S.R.
No Member Body opposed the approval of the Draft.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0
Council, which decided, in February 1961, to accept it as an IS0 RECOMMENDATION.
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lSO/ R 173 - I961 (E)
IS0 Recommendation R 173 February 1961
PLASTICS
DETERMINATION OF THE PERCENTAGE OF STYRENE
IN POLYSTYRENE WITH WIJS SOLUTION
1. SCOPE
The purpose of this IS0 Recommendation is to describe a procedure for determining the percen-
tage of monomeric styrene and other unsaturated compounds in unmodified polystyrene by
measuring the degree of unsaturation of polystyrene with iodine monochloride, the results being
expressed as monomeric styrene.
The test supplements the method for the determination of percentage methanol soluble matter
of polystyrene, as it usually shows whether a high value of methanol soluble matter is due to a
high styrene content or to the presence of substances other than styrene, e.g. lubricant.
2. APPARATUS
The apparatus consists of the following:
2.1 Means of reducing the material to a powder.
2.2 Sieve with apertures 1.5 to 2.0 mm square.
2.3 Graduatedflask, 250 ml.
Bottle, glass-stoppered, of about 500 ml capacx,y.
2.4
2.5 Balance to weigh to 0.001 g.
3. REAGENTS
The following reagents are required:
Potassium iodid
...