Release from Composites by Mechanical and Thermal Treatment - Safety of Nanomaterials along Their Lifecycle - page 250

Aerosol flow

Sampling
hood

Sampling
point

Sanding
machine

Abrasion wheel
(sanding machine)

Sampling
point

Sample carrier

FIGURE 12.3 3D-CAD model of the test device employed for sanding with marked sam-
pling hood. (Adapted from Göhler, D. et al., Characterization of nanoparticles release from
surface coatings by the simulation of a sanding process, 2010, by permission of Oxford
University Press.)

TABLE 12.1
Comparison of Characteristic Values between the
Employed Miniature Sander and Professional Sanding
Processes

Sander (Dremel) Typical Sanding Process

Contact force (N) 0.2-1.0 400-40,000

Contact pressure (Pa) 10,000-50,000 3,000-20,000

Peripheral speed (m/s) 1.8-24 3.0-17.0

Source: Adapted from Göhler, D. et al., Ann. Occup. Hyg ., 54, 615-624, 2010.

The sanded surface was a rectangular area of 13 cm², the contact pressure 10 kPa,
the relative peripheral speed 1.83 m/s, and the sanding paper was P600 with a grit
size of 25.8 µm. The abraded material during sanding was continuously sucked
through the sampling hood (see aerosol flow in Figure 12.3). The employed measure-
ment instruments, an FMPS, a laser aerosol particle sizer, and a condensation particle
counter (CPC), received the sample flows through a flow splitter installed directly
behind the sampling hood. A comparison of the characteristic parameters between
the used sander and typical industrial sanding processes is given in Table 12.1.
Five different coatings (without nanoparticle [NP] and with ZnO or Fe 2 O 3 -NP)
were examined in this sanding study in five repetitions. The results show consider-
able generation of nanoparticles by the sanding process, but with no significant dif-
ference between coatings containing nanoparticle additives and without additives.
Furthermore, the measurements exhibit a large spread in the released particle con-
centrations even though the swarf mass data were in a reasonable agreement.
Cena and Peters (2011) conducted a study in a facility that produces test samples
composed of epoxy reinforced with carbon nanotubes (CNTs). The test samples of
different formulations and hence different properties of the nanocomposites were