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Physical & Chemical properties

Nanomaterial agglomeration / aggregation

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Administrative data

Endpoint:
nanomaterial agglomeration/aggregation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010-2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2011

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: internal method ASM.MDA.024
Principles of method if other than guideline:
Internal standard ASM.MDA.024: "Qualitative characterization of Carbon Nanotube powders by scanning electron microscopy".
GLP compliance:
no
Other quality assurance:
other: ISO 9001 Standard
Type of method:
scanning electron microscopy
Details on methods and data evaluation:
Ten balls with irregular "macroscopic" appearence are located on one to three surveys of CNT balls (SEM images at a magnification of 100 times). An image is taken at magnification of 5000 times or 10000 times of specific places to visualize some little aggregates. Then, more accurate obeservations require magnification of 20000 times,30000 times, 40000 times, 50000 times, 60000 times or 100000 times to try to see the borders or the interconnections between little aggregates within a ball.
The secondary electron "SE" detector is used for the views at low magnification of 100 times, the "in lens" detector (at th extremity of the electon) is used for the views at higher magnifications.
Sampling:
- Preparation of test samples and references: Sample preparation: CNT powder is spread onto a microscopy sample holder covedred with a carbon two-sided adhesive tape. The sample holder is tapped on a moistened paper set down on the table (under the ventilated hood) in order to remove the excess of powder. Three replicates of the same sample can be prepared in the same way.
CNT observation is carried out without metallization.

- Measurement procedure: The sample holder is carried to the microscope in a closed box and observations were performed under high vacuum and under a voltage of 5kV.

Test material

Constituent 1
Chemical structure
Reference substance name:
Tangled Multi-Walled Carbon Nanotubes
EC Number:
701-160-0
Cas Number:
7782-42-5
Molecular formula:
Hollow tubular carbon, 1-dimensional nano structures with hexagonal arrangement of carbon atoms
IUPAC Name:
Tangled Multi-Walled Carbon Nanotubes
Constituent 2
Reference substance name:
GRAPHISTRENGTH C100
IUPAC Name:
GRAPHISTRENGTH C100
Test material form:
solid: nanoform
Specific details on test material used for the study:
The CNT can be exmined in the microscope without any other preparation or, when necessary, the sample can be metallized with gold to enhance its electric conductivity, before being examined in the microscope.
The different stages from the starting up of the miscroscope, the complete gun and column alignment, to the particular working modes are described in a detailed manner in the operating manuals provided by instrument manufacturer.
To study "aggregation" or "agglomeration", CNT observation is carried out without metallization, under high vaccum and under a voltage of 5 kV.

Data gathering

Instruments:
Scanning Electron Microscope ZEISS Leo type 1530 model VP equipped with and X-rays analyser OXFORD type "Energy 200".

Results and discussion

Any other information on results incl. tables

For the "aggregation" or "agglomeration" characterization, the results are given in the form of numeric images in .jpeg format. Only qualitative results can be given by SEM images.

Applicant's summary and conclusion

Conclusions:
In carbon nanotube powder of the test item, carbon nanotubes were entangled, connected to each othe inside the same ball; some entangled nanotubes went from one aggragate to another aggregate inside the same ball.