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Surface tension

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Reference
Endpoint:
surface tension
Type of information:
experimental study
Adequacy of study:
key study
Study period:
March 16-22, 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 115 (Surface Tension of Aqueous Solutions)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.5 (Surface Tension)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
OECD harmonised ring method
Key result
Surface tension:
46 mN/m
Temp.:
20 °C
Conc.:
8.4 mg/L
Remarks on result:
other: The surface tension was determined at the CMC, considering it as an approximation of the water solubility limit.

- Since methanol was used as a solubilising agent in preparing the test solutions, the impact of methanol (for a concentration range 0.05 - 1.25 mL/L) over the surface tension of water was also evaluated in this test and was found to have no effect.

- The critical micelle concentration (CMC) was determined to be 8.4 mg/L.

-The surface tension of the Amides, coco, N-(2-hydroxypropyl) solution was found to decrease with increasing concentrations until the critical micelle concentration at 8.4 mg/L was achieved. At concentrations higher than this CMC value, the surface tension remained nearly unchanged.

The results for surface tension for the different test material concentrations are shown in the below table.

Amides, coco, N-(2-hydroxypropyl) content, mg/L

Measurement result,

mN/m

Multiplied by thecalibration factorΦb,,

mN/m

After correction,

mN/m

Average ±

std. dev.

mN/m

 

0.04

69.9

72.7

72.8

 

72.9 ± 0.1

70.1

72.9

73.1

70.0

72.8

72.9

 

0.40

63.2

65.7

65.3

 

67.6 ± 2.8

68.0

70.7

70.7

64.5

67.1

66.7

 

2.00

57.8

60.1

59.3

 

60.7 ± 2.3

58.0

60.3

59.5

61.5

64.0

63.4

 

3.00

56.5

58.8

57.8

 

57.8 ± 0.0

56.5

58.8

57.8

56.5

58.8

57.8

 

4.00

52.5

54.6

53.4

 

55.0 ± 1.5

54.0

56.2

55.1

55.3

57.5

56.5

 

5.00

48.0

49.9

48.5

 

49.8 ± 1.1

49.5

51.5

50.1

50.0

52.0

50.7

 

10.00

45.5

47.3

45.8

 

45.7 ± 0.1

45.3

47.1

45.6

45.5

47.3

45.8

 

20.00

36.0

37.4

35.6

 

35.3 ± 0.3

35.6

37.0

35.2

35.5

36.9

35.1

 

30.00

35.3

36.7

34.9

 

35.0 ± 0.1

35.5

36.9

35.1

35.5

36.9

35.1

 

40.00

35.5

36.9

35.1

 

35.0 ± 0.1

35.3

36.7

34.9

35.5

36.9

35.1

 

50.00

35.2

36.6

34.8

 

34.8 ± 0.1

35.3

36.7

34.9

35.3

36.7

34.9

The dependence of the surface tension on the concentration has been shown in the attached background material

Conclusions:
The surface tension of amides, C8-18 and C18 (unsatd.), N-(2-hydroxypropyl) at its critical micelle concentration (8.4 mg/L), using the determined surface tension concentration dependence, was calculated to be 46.0 mN/m.
Executive summary:

The surface tension of the test substance was determined according to OECD Guideline 115 and EU Method E.5. The surface tension was determined at the critical micelle concentration (CMC), considering this value as an approximation of the water solubility limit. The surface tension of the test substance was 46.0 mN/m at 20ºC and 8.4 mg/L (Lewandowska, 2010).

Description of key information

The surface tension was determined according to OECD Guideline 115 and EU Method E.5 (Lewandowska, 2010).

Key value for chemical safety assessment

Surface tension:
46
in mN/m at 20°C and concentration in mg/L:
8.4

Additional information