Field and Laboratory Measurements Related to Occupational and Consumer Exposures - Safety of Nanomaterials along Their Lifecycle - page 304

TABLE 13.4 ( continued )
Publications Describing Scenarios Related to Source Domain 4

Observed NM
Release

Reference Scenario Nanomaterial Metric Summary/Conclusions

Fleury et al.
(2013)

Grinding, cutting CNT Yes, no isolated

CNT and strange
aggregates

PSD, PNC (7
nm-10 μm)

The grinding process generates a large amount of airborne
particles, mostly small pieces of polymer containing CNT,
which seems roughly proportional to the quantity of polymer
introduced into the grinder. As this process does not involve
heating, the CNTs stay stuck into the matrix and the
probability to aerosolize ibers might be very small. A blank
test was performed by running the grinder empty. It reveals an
emission leading to very small-particle concentrations
probably resulting from friction of rotating elements and
blades, plus the natural emission of the electric motor. 10 min
after the introduction of nanocomposites into the grinder, the
measurement devices show a particle concentration of 3 × 10 3
#/cm 3 mainly composed of diameter below 50 nm (average
size is close to 20 nm)

Hirth et al.
(2013)

High energy
abrasion/
sanding,
nanocomposites

CNT STEM images,

elemental
mapping, and
photoelectron
line shape
analysis

PSD (SMPS)
PSD of
fragment

Scenarios of high-energy input (sanding) and of dry and wet
weathering were simulated to the polymer matrix to investigate
the airborne particles released from polymer nanocomposites.
Protrusions of CNTs from fragments of CNT-epoxy and
CNT-cement composites after sanding were observed, whereas
such protrusions were not observed for CNT-
polyoxymethylene and CNT-polyurethane fragments.
There is no indication of freely released CNTs from mechanical
forces alone. Based on size characterization with validated
methods, at least 95 wt% of the CNT nanoillers remain
embedded