Chemical Engineering August 2021 - 14

been working
on improving
specific
properties so
the polymers
can be used
in new applications, "
Havenith
explains.
FiGURE
1. The shift from propulsion by liquid fuels to propulsion by battery has
highlighted the importance of plastic materials with specific properties
teries & Electrical segment, SABIC's
Petrochemicals
business
explains:
" The battery pack is the most expensive
assembly ever fitted to a vehicle.
At the same time, mass [of the car] is
an important variable - more mass
means more energy required. All of a
sudden, you need more battery storage,
bigger brakes and so on. "
" Despite the industry's best efforts, "
Nagwanshi says, " the addition
of new technology and content continues
to increase the overall curb
weight of vehicles. The good thing
about thermoplastic materials is their
powerful combination of structural
strength and low density. When you
can remove mass and weight by, for
example, replacing aluminum in battery
packs with plastic, you can theoretically
reach a point where battery
cells can be removed because you
no longer need as much energy for
the same amount of range. "
In addition, Nagwanshi points out,
thermoplastics can contribute to additional
cost savings by eliminating
the need for adhesives and fasteners,
and for die casting, welding and
other processes.
Generally, the polymer types that
are used for automotive applications
have been known for quite
awhile, says Bert Havenith, market
intelligence and sustainability director
at DSM N.V. (Geleen, the Netherlands;
www.dsm.com). " But there
has been significant innovation in
ways to functionalize the materials
through compounding processes so
that they are able to exhibit improved
properties for a wide variety of parameters.
DSM, among others, has
14
In an example
of the
incr eased
demand for
compounding
of engineered
plastics,
Celanese Corp. (Irving, Tex.;
www.celanese.com), announced
a three-year plan to expand engineered
materials
compounding
capacities at the company's Asia
facilities, including the locations of
Nanjing, China; Suzhou, China; and
Silvassa, India. The initiative will add
approximately 52,000 tons of compounding
and long-fiber thermoplastics
(LFT) capacity at the company's
Nanjing chemical complex by
the second half of 2023, as well as
nylon compounding capacity at the
Suzhou facility in 2022.
Glass-reinforced plastics
For making metal-replacement structural
components in BEVs, where
strength and stiffness at light weights
is a premium, glass fibers are among
the most common materials found
in plastics. Significant focus has
been leveled at processing glassreinforced
plastics, with the automobile
market a major emphasis.
BASF's Korson points out the impact
of one kind of processing technique,
known as pultrusion, on EVs. " New
EV architectures lend themselves
to pultrusion-made parts, " he says,
" and BASF has done a lot of work on
pultrusion processing for composite
materials, and have pushed pultrusion
to achieve higher throughputs. "
Pultrusion is a processing technique
in which glass fibers are pulled
through a bath of polymer resin.
Earlier this year, BASF introduced
serial production of glass-fiber polyurethane
parts made in a pultrusion
process. " There are lots of opportunities
in the future for pultrusion materials
in EVs, " Korson says. Another
important factor in the adoption of
pultrusion in the automotive market
is the ability to model pultruded components
in computer simulation to
accurately predict the behavior in the
full vehicle system. This is important
for original equipment manufacturers
(OEMs) and Tier 1 suppliers to design
pultruded parts early in the vehicle
development. Engineers are also
working on ways to modify the glass
fibers before they are introduced into
the resin bath for different properties
based on the applications needs.
Evonik recently introduced a number
of products that will be used in
the BEV market, including a new
polyamide-12 polymer of the group's
Vestamid L grades, a glass-reinforced,
electrically conductive PA12
molding compound that was developed
in particular for the injection
molding of connecting elements for
fuel line systems (such as quick connectors).
The electrical conductivity
of the new Vestamid L changes only
slightly on contact with fuels, even if
they contain alcohol. This is of great
importance for use in fuel-conducting
systems, Evonik says.
Lightweighting
Automotive engineers have long
known the relationship between
lowering vehicle weight and raising
fuel economy. A rule of thumb in
the auto industry has been that for
a 10% reduction in weight, the fuel
efficiency of the vehicle improves by
6-8%. In BEVs, vehicle lightweighting
allows longer ranges for a given
battery size or achieving the same
range with a smaller (and therefore
less costly) battery.
" Lightweighting by replacing metal
parts with plastics is a priority across
the board for vehicles, but most of
the 'low-hanging fruit' in this area
has been realized already, " says
Mark Jablonka, application technology
leader for transportation at
Dow Packaging and Specialty Plastics
(Lake Jackson, Tex.; www.dow.
com). Among the implications
for
this is that BEV makers are looking
at every existing component for
ways to cut weight. " The use of TPO
[thermoplastic olefin; polypropylene
(PP)-based composites containing
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Chemical Engineering August 2021

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