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Physical & Chemical properties

Surface tension

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Reference
Endpoint:
surface tension
Type of information:
experimental study
Adequacy of study:
key study
Study period:
6th August 1999 to 11th February 2000
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of relevant results.
Reason / purpose:
reference to other study
Qualifier:
according to
Guideline:
EU Method A.5 (Surface Tension)
Deviations:
yes
Remarks:
No Harkins-Jordan correction.
Qualifier:
according to
Guideline:
other: ISO 304
GLP compliance:
yes (incl. certificate)
Remarks:
Date of inspection: March 23rd 1998 Date of signature: July 21st 1998
Type of method:
ring method
Key result
Surface tension:
50.7 mN/m
Temp.:
21.5 °C
Conc.:
1.138 g/L

Calibration factor (water)

Mean calibration factor (n=5) = 1.001

The readings, times and temperatures for the sample solution are shown in the following table:

Time (mins)

Reading (mN/m)

Temperature (°C)

70

50.5

21.5

85

50.6

21.5

100

50.7

21.5

115

50.5

21.5

Corrected surface tension = mean reading x calibration factor = 50.6 x 1.001 = 50.7 mN/m

The surface tension result was not corrected using the Harkins-Jordan correction table as the correction is not applicable to the apparatus used. Once calibrated, the balance and ring assembly used in this test give a direct reading for surface tension that is within the required accuracy (+/- 0.5 mN/m); this is a result of the reduced ring dimensions.This deviation has been considered not to have affected the integrity of this study.

Conclusions:
As the result is below the threshold value of 60 mN/m, according to EU A5 criteria, the substance is considered to have surface-active potential under the experimental conditions.
Executive summary:

Method: The determination was carried out using a interfacial tension balance and a procedure based on the ISO 304 ring method. With the exception of the deviation described previously, the experimental procedure used complied with that specified in EU Method A5.

Discussion: Although the results of this test shows ST 03 C 99 is surface active, ST 03 C 99 does not have the chemical structure typical of a surfactant. Nor does ST 03 C 99 show some of the properties associated with surfactants, e.g., causing emulsification in a two-phase organic/aqueous system.

Results & Conclusion: The surface tension of a 1.138 g/L solution of ST 03 C 99 was determined to be 50.7 mN/m at 21.5 +/- 0.5°C.

Description of key information

Experimental surface tension on a ca 90% saturated solution at 21.5°C.
According to EU A5 criteria, as the result is below the threshold value of 60 mN/m, the substance is considered to have surface-active potential under the experimental conditions. However, since the structure is not characteristic of a true surfactant, and it is not the intended use of the substance (i.e. not a desired property), this conclusion should be taken with caution.

Key value for chemical safety assessment

Surface tension:
50.7
in mN/m at 20°C and concentration in mg/L:
1 138

Additional information

An experimental study on surface tension measurement of the test material, was conducted under GLP, and considered as fully reliable. Therefore the result is considered as key data.

Although the result of this assay shows that the test material is surface active, it does not have the chemical structure typical of a surfactant. Nor does it show some of the properties associated with surfactants, e.g., causing emulsification in a two-phase organic/aqueous system.