JEC COMPOSITES MAGAZINE - Issue #79 - March 2013 - 106

nano

106 jec composites magazine / No79 March 2013

for nanocomposite and conductive applications as well as projects where structural
characteristics are important. Thicker, longer platelets are typically used for electrical
applications.

Performance attributes
While the performance attributes of
graphene continue to make it attractive
to researchers and manufacturers, interest
is also due in part to its ability to enhance
other materials as an additive. Composites
infused with graphene have demonstrated
stronger, stiffer performance attributes and
are less prone to failure than composites
infused with carbon nanotubes or other
nanoparticles. This means graphene could
be a key enabler in the development of
next-generation nanocomposite materials.
For a manufacturer who is looking to purchase graphene, the basic quality checklist
is a high grade of raw material, repeatability
of material consistency from order to order
and sound processing and manufacturing methods. In addition to considering
graphene’s physical make-up and its potential application uses, manufacturers should
also consider whether or not the material
has been properly tested to ensure quality.
Angstron tests the chemical purity of its
graphene products in-house. BrunauerEmmett-Teller measurements help assess
and ensure the specific surface area of the
graphene products. The x and y average size
is measured using a particle analyzer which
gives an equivalent x and y dimension. The
company also uses microscopies including optical, SEM and TEM to check the
quality of samples. The shape of graphene
particles is examined using these methods
Angstron is the first advanced materials company to offer large quantities
of ultra-thin, pristine nano-graphene
platelets (NGPs). The company is also
significantly reducing production cost
barriers with its high-performance
nano-graphene solutions. A new 6,096
square metre manufacturing facility,
based in Dayton, Ohio, allows
Angstron to continue its research and
development efforts while providing small
to large batch processing and production.

More information ...

the nano-graphene
platelets. For
powder forms of
graphene, technical
data should show
oxygen content for
quality graphene
ranging from 0.80
to 2.10%. Specific
surface area can,
depending on the
application, can be
as small as 13 m²/
gm or as high as
800 m²/gm. Average x and y dimensions typically fall
with the range of
5 to 44 µm while z
dimensions (thickness) can average
less than 1 nm up
to 100 nm. Carbon
content for powder
graphene should
be between 97 and
99%. In the case
of graphene oxide
Fig. 1: Angstron’s quality control manager Lucy Fu evaluates the specific
(liquid form), the
surface area of a graphene sample by taking Brunauer-Emmett-Teller
average thickness
measurements.
or z dimension
The company’s work with NGPs and
for quality material ranges from less than
NGP nanocomposites has tended to target
1 nm up to 1.2 nm with x and y dimenother key performance characteristics such
sions at most 554 µm. Carbon content for
as:
graphene oxide in a water-based solution
- Highest thermal conductivity known
is approximately 46%. Manufacturers can
today (up to ~ 5,300 W/(mK) for faster
begin to fine tune their criteria once an
thermal dissipation
application has been identified. For com- Exceptional in-plane electrical conductipanies working in the areas of conductive
vity (up to ~104 S/cm)
composites, barriers, energy or solar cells,
- A material density four times lower than
nanocomposites, capacitors, conductive
copper resulting in lighter weight compoinks and organic semiconductors, quality
nents
graphene material is generally provided in
- High specific surface area (up to ~ 2,675
a powder form. Usually a graphene oxide
m2/g) for energy storage or heavy metals
water-based solution is suited for appliadsorption
cations where higher levels of oxygen are
- Resistance to gas permeation
required. The graphene oxide solution can
also be used for transparent electrodes,
Application requirements
capacitors and barriers, and biological and
While application requirements also factor
medical products.
into the choice of graphene, a manufacOne of the most critical attributes is
turer can use a company’s technical data
thickness or the z dimension. Thinner
measurements to evaluate the quality of
graphene platelets are generally best suited

JEC COMPOSITES MAGAZINE - Issue #79 - March 2013

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