Biomedical Engineering Reference
In-Depth Information
2012). Kaiser et al. (2013) have recently discussed the possibilities of application of
several of these MN in paints and lacquers.
Due to the nature of the paint and lacquer products, consisting of a mixture of
passive and functional fillers in a liquid matrix, it is evident that they may be associ-
ated with great risk of exposure not only during production and downstream use but
also during renovation and removal of coated surfaces. However, there is currently
limited knowledge available on the specific hazards of the MN used in such surface
coatings and the exposure risks at the different lifecycle stages. Moreover, surface
modification of the MN is often necessary to enable good dispersion and binding
to the product matrix. In other cases doping of the primary MN is done to achieve
antimicrobial properties. Due to these surface modifications and doping, the poten-
tial hazards associated with paint MN may not be limited to the core material alone.
Consequently, the MN producers as well as the paint and lacquer manufacturers
using MN have a difficult task of ensuring the safety of workers, consumers, and the
environment.
In this chapter, we give an overview of the typical silica nanomaterials used in
experimental and produced paints and lacquers, emission characteristics of dusts
generated by abrasion testing of such surface coatings, and their associated potential
human hazard.
17.2 EXAMPLES OF SILICA NANOMATERIALS
USED IN PAINTS AND LACQUERS
The use of silica MN may improve several different mechanical paint or lacquer
properties, including increased strength and scratch resistance, hydrophobicity,
high gloss, thermal stability/fire resistance, and resistance to ultraviolet (UV) light
(Kaiser et al. 2013; Mizutani et al. 2006; Zhu et al. 2008). In other applications, silica
nanoparticles are used or proposed as a carrier or doped composite nanomaterial to
achieve well-controlled biocide release properties (Chmielewska et al. 2006; Edge
et al. 2001; Kristensen et al. 2010; Lukasiewicz et al. 2003; Sørensen et al. 2010). In
the following sections, we highlight some of the silica MN that have been used in
experimental and commercial paints and lacquer products.
17.2.1 e
xamPles
of
n
anosiliCa
u
sed
to
i
mProve
m
eChaniCal
P
roPerties
Nanosilica (primary particle diameter 15-25 nm) was used to produce a superhydro-
phobic low-friction epoxy paint (Karmouch and Ross 2010). The optimum perfor-
mance was observed at 2-3 wt% silica nanoparticles.
Another example of silica use is in a nanocomposite emulsion for wall paint pro-
posed as a replacement for traditional solvent-type paints. In this case, 17 wt% of ca.
60 nm-size polyacrylate-coated silica (silica core diameter ca. 30 nm) was added to
an acrylic paint replacing mainly the acrylic resin (Mizutani et al. 2006). The per-
formance of this product was compared to the performance of a commercial acrylic
paint and a conventional solvent-type paint. The pigment and filler content in the sol-
vent-type paint was 30 wt%, whereas it was only 21 wt% in the commercial paint. In
the nanocomposite paint, the total pigment and filler content was 38 wt%, including
Search WWH ::
Custom Search