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Particle size distribution (Granulometry)

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Endpoint:
particle size distribution (granulometry)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
July 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well conducted study, according to EU and OECD guidelines, with Internal management system and certificate of analysis included in the report.
Qualifier:
according to
Guideline:
other: ISO 2591-1, Test sieving – Part 1: Methods using test sieves of woven wire cloth and perforated metal plate, December 1988
Deviations:
no
Qualifier:
according to
Guideline:
other: ISO 3310-1, Test sieves – Technical requirements and testing – Part 1: Test sieves of metal wire cloth, July 1990
Deviations:
no
Qualifier:
according to
Guideline:
other: AkzoNobel SMA 721.02, Determination of the particle size distribution of powders and granular products
Deviations:
no
Qualifier:
according to
Guideline:
other: AkzoNobel SMA 743.02, Distribution of powders and granulated products in representative portions, August 1993
Deviations:
no
Qualifier:
according to
Guideline:
other: DRAFT EUR 20268 EN Guidance document on the determination of particle size distribution, fiber length and diameter distribution of chemical substances, 2002
Deviations:
no
GLP compliance:
no
Remarks:
Internal Management System
Type of method:
sieving
Type of distribution:
mass based distribution
Percentile:
D50
Remarks on result:
other: Migrated from fields under 'Mass median diameter' as D50 percentile. No source field for Standard deviation.
No.:
#1
Size:
< 100 µm
Distribution:
> 0.23 - < 0.31 %

Sieving

The result from sieving the samples is shown in the table below.

 Determination fraction < 100µm

Fraction

Sample 1

Sample 2

Sample 3

 

[g]

[%]

[g]

[%]

[g]

[%]

< 100 µm

0.24

0.23

0.25

0.24

0.33

0.31

> 100 µm

103.77

99.77

101.83

99.76

105.99

99.69

 

It is concluded that less than 1% w/w of the product passes the sieve. Consequently no PSD has to be determined.

Light microscopic examinations

Pictures of the fraction < 100 µm were taken with the Stemi 2000-c microscope assembled with an AxioCam ICc 3 digital camera.

See picture of dihexadecyl peroxodicarbonate, fraction < 100 µm in the attachment.

 

This picture shows that the shape of these fines is non-fibrous.

Conclusions:
Less than 1% w/w of dihexadecyl peroxodicarbonate flakes passes the 100 µm sieve. Consequently no PSD measurement of the fraction < 100 µm has to be performed .

Light microscopic examination revealed that the Dihexadecyl peroxodicarbonate particles < 100 µm are non-fibrous.
Executive summary:

The granulometry of Dihexadecyl peroxodicarbonate was determined in accordance with European Chemicals Agency (ECHA), Guidance on information requirements and chemical safety assessment, Chapter R.7a, Endpoint specific guidance, May 2008.

 

Sieving of the product on a 100 µm screen revealed that less than 1% w/w is < 100 µm. No further examination of the PSD of this fraction was required. However a microscopic picture was made which showed that the particles < 100 µm have a non-fibrous shape.


Endpoint:
particle size distribution (granulometry)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
July 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well conducted study, according to EU and OECD guidelines, with Internal management system and certificate of analysis included in the report.
Qualifier:
according to
Guideline:
other: ISO 2591-1, Test sieving – Part 1: Methods using test sieves of woven wire cloth and perforated metal plate, December 1988
Deviations:
no
Qualifier:
according to
Guideline:
other: ISO 3310-1, Test sieves – Technical requirements and testing – Part 1: Test sieves of metal wire cloth, July 1990
Deviations:
no
Qualifier:
according to
Guideline:
other: AkzoNobel SMA 721.02, Determination of the particle size distribution of powders and granular products
Deviations:
no
Qualifier:
according to
Guideline:
other: AkzoNobel SMA 743.02, Distribution of powders and granulated products in representative portions, August 1993
Deviations:
no
Qualifier:
according to
Guideline:
other: DRAFT EUR 20268 EN Guidance document on the determination of particle size distribution, fiber length and diameter distribution of chemical substances, 2002
Deviations:
no
GLP compliance:
no
Remarks:
Internal Management System
Type of method:
sieving
Type of distribution:
mass based distribution
Percentile:
D10
Mean:
36.4 µm
St. dev.:
0.3
Percentile:
D50
Mean:
65.1 µm
St. dev.:
0.7
Percentile:
D90
Mean:
97.3 µm
St. dev.:
1.6
No.:
#1
Size:
< 100 µm
Distribution:
3.6 %

Sieving

The average result from the sieving of sample 1 and 2 is shown in the table below. To enhance the sieving performance, first a 500 µm screen was used. This separates the bulk of the material from the smaller particles. Afterwards the size of the fractions > 500 µm and 100 - 500 µm were summed.

 

Determination fraction < 100µm

Fraction

Sample 1

Sample 2

 

[g]

[%]

[g]

[%]

< 100 µm

17.95

3.6

18.10

3.6

> 100 µm

487.08

96.4

485.93

96.4

 

It is concluded that there are more than 1%m/m particles < 100 µm present and therefore the PSD of this fraction was determined.

Light microscopic examinations

Pictures of the fraction < 100 µm were taken with the Stemi 2000-c microscope assembled with an AxioCam ICc 3 digital camera. See attachment.

Dihexadecyl peroxodicarbonate, fraction < 100 µm

 

This picture in the attachment shows that the shape of these fines is non-fibrous.

PSD by laser diffraction

The PSD of the fraction < 100 µm is determined by laser light diffraction. The results are given in the attachment. The average is given in table below.

 

PSD of fraction < 100 µm, average of both samples

 

d10

d50

d90

[µm]

[µm]

[µm]

Average

36.4

65.1

97.3

St. Dev.

0.3

0.7

1.6

 

From the underlying data it is calculated that from the fraction < 100 µm only 0.01% is < 10 µm and 0.00% is < 5 µm. For the whole product it means:

< 10 µm: 0.036%

< 5 µm: 0.0%

Conclusions:
Sieving of Dihexadecyl peroxodicarbonate L on a 100 µm screen showed that 3.6 %m/m particles < 100 µm are present. This exceeds the 1% m/m threshold.
Light microscopic examination revealed that the Dihexadecyl peroxodicarbonate L particles < 100 µm are non-fibrous.
The characteristics of the PSD of the fraction < 100 µm are:
d10 36.4 µm
d50 65.1 µm
d90 97.3 µm
From the whole product 0.036% is < 10 µm and 0.0% is < 5 µm.
Executive summary:

The granulometry of Dihexadecyl peroxodicarbonate was determined in accordance with European Chemicals Agency (ECHA), Guidance on information requirements and chemical safety assessment, Chapter R.7a, Endpoint specific guidance, May 2008.

 

Sieving of the product on a 100 µm screen revealed that 3.6% w/w is < 100 µm. Light microscopic examination of this fraction showed that these fines are non-fibrous.

 

The PSD characteristics of this fraction are reported in the table below.

 

Characteristics of the PSD

d10

36.4 µm

d50

65.1 µm

d90

97.3 µm

 

From the whole product 0.036% is < 10 µm and 0.0% is < 5 µm.

Description of key information

Light microscopic examination revealed that both samples  Dihexadecyl peroxodicarbonate particles < 100 µm are non-fibrous.

Dihexadecyl peroxodicarbonate FL ( flakes) consists of  less than 1% w/w 100 µm particles. Consequently no PSD measurement of the fraction < 100 µm has to be performed .

Dihexadecyl peroxodicarbonate L has  3.6 % m/m particles < 100 µm. This exceeds the 1% m/m threshold.

The characteristics of the PSD of the fraction < 100 µm are:

d10       36.4 µm

d50       65.1 µm

d90       97.3 µm

From the whole product L 0.036% is < 10 µm and 0.0% is < 5 µm.

Additional information

The Particle size distribution (Granulometry) differ because of differences in physical appearance (flakes/powder) and purity of the samples.