Chemical Engineering April 2023 - 6

using commercially available
reagents - polysilazanes,
carbinol silicones and silanolterminated
silicones - under
ambient conditions.
Coatings and elastomers prepared
by this methodology
show the same characteristics
as the corresponding silicone
coatings and elastomers prepared
by classical methods,
even though the curing methodology
is very different. Specific
organic catalysts can be
added to control the curing
rate, permit coating and fast
drying processes, and control
cure kinetics. For all the mentioned
systems, this technique
will enable the removal of tin
and platinum catalysts from
current products. The patented
method, which is available
for license, is described in
a recent article in Macromolecular
Materials and Engineering.
EATING GRASS?
Dutch companies Schouten
Europe B.V. (Giessen; www.
schoutenfood.com) and Grassa
B.V. (Venlo; www.grassa.nl)
started a collaboration to develop
meat substitutes using
protein from grass as an alternative
to soy protein. " Grass
protein has massive potential, "
says Rieks Smook, director of
Grassa. " Grass yields 2.5 times
as much protein per hectare as
soy. Grass supplies are readily
available. Grass protein is a
high-quality, local and scalable
alternative to soy. When compared
to other protein sources,
it provides a huge reduction in
the carbon footprint. "
Grassa produces grass protein
in its demonstration factory
in Afferden. This protein
is currently being used to codevelop
products in pet food,
aqua feed and compound feed
for pigs and chickens. In addition,
Grassa has tested and developed
technologies to extract
protein from grass that is suitable
for human applications.
FUNGUS-BASED FOOD
Last month, the University of
Borås (Sweden; www.hb.se)
announced another milestone
in its more than 20 years of
research on fungi - a company
will now use the findings
to produce a completely new
(Continues on p. 8)
6
A new milestone for durable
fuel-cell membranes
F
or the first time, a hydrocarbonbased
membrane has passed the
performance and durability testing
standards set by the U.S. Dept.
of Energy (DOE; Washington, D.C.; www.
energy.gov) for heavy-duty fuel-cell applications.
Typically, membranes in fuel cells
are made of perfluorinated materials like
perfluorosulfonic acids (PFSAs), but such
materials have several drawbacks, including
significant environmental concerns and
high costs for end-of-life precious-metal
recovery. Pemion proton-exchange materials,
developed by Ionomr Innovations
Inc. (Vancouver, B.C., Canada and Rochester,
N.Y.; www.ionomr.com), include no
perfluorinated
compounds, and create
membranes that are said to be significantly
more durable than previous hydrocarbonbased
attempts.
" Pemion is a composite membrane.
The polyarylene polymer is reinforced with
hydrophobic materials that enable the dimensional
stability required for system integration,
while maintaining high throughplane
conductance, " explains Ben Britton,
Ionomr's chief strategy officer. " The Pemion
ion-exchange polymer benefits from
a novel synthetic protocol that allows for
extreme consistency of properties, includC
hemical
recycling of waste polyolefins
difficult
to
achieve
ing
the same degree of functionality every
time, eliminating concerns about batch-tobatch
reproducibility often seen in other
materials, perfluorinated or not, " he adds.
Furthermore, unlike PFSA materials, Pemion
polymers are thermochemically stable
up to 180°C, enabling a development
platform for other fuel-cell components to
reach industry operating targets of 120°C.
Pemion membranes underwent combined
chemical and mechanical stability
accelerated stress tests designed for
fuel-cell membranes, as well as the DOE
relative-humidity (RH) cycling mechanicaldurability
protocol. The tests, which were
run for over 40,000 cycles with electrochemical
assessments every 24 h, demonstrated
stability of the membrane in various
membrane electrode assembly (MEA)
configurations. " Critically, MEAs containing
Pemion membranes exhibited minimal
thinning, minimal decreases in opencircuit
voltage throughout the lifetime of
the test and exceptionally low gas crossover,
which increases cell efficiency and
lifetime, " says Britton.
Beyond fuel cells,
Ionomr sees applicability for the Pemion
polymer membrane in electrochemical hydrogen
compressors, sensors and humidifiers,
as well as utility of the polymer itself in
battery technologies.
Converting waste polyolefins to isoalkanes
is
economically partly because
of the stability of carbon-carbon
bonds in the plastics. In a new approach,
researchers at Pacific Northwest
National Laboratory
The C-C bond cleavage is followed by
a targeted alkylation to form high-quality
liquid alkanes using catalysts developed
for petroleum refining.
(PNNL; Richland,
Wash.; www.pnnl.gov) and the Technical
University of Munich (www.tum.de) have
taken a step toward lowering the energy
required to cleave the C-C bonds and directing
the production of fuel products. To
do this, they created a highly ionic reaction
environment and combined the polymer-cracking
reaction with a subsequent
alkylation
reaction in the same vessel.
Using this process, the team was able to
produce gasoline-like C6-C10 isoalkanes
from polypropylene (PP) and low-density
polyethylene (LDPE) waste.
Publishing in a recent issue of the journal
Science, the research team reported
an aluminum-chloride-based ionic-liquid
medium that promotes the breakdown of
the plastics. Specifically, the ionic medium
" increases the polymer reactivity and lowers
the energy of ionic transition states, "
the researchers say.
PNNL chemist and study co-author Oliver
Gutierrez explains that cracking and
bond breakage can lead to uncontrolled
bond formation, which can be a problem
in other approaches. " The secret formula
here is that when you break a bond in our
system, you immediately make another
one in a targeted way that gives you the
end product you want, " he says. And
combining the endothermic cleavage of
the polymer C-C bonds with exothermic
alkylation reactions of the cracking products
enables full conversion of LDPE and
PP to liquid isoalkanes at temperatures
below 100°C. The alkylate product forms
a separate phase that is easily separated
from the reactant catalyst mixture, the researchers
say.
In their study, the researchers note the
process works for LDPE and PP, but highdensity
polyethylene (HPDE) would require
a pretreatment to allow the catalyst access
to the bonds it needs to break.
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
APRIL 2023
http://www.energy.gov http://www.ionomr.com http://www.schoutenfood.com http://www.grassa.nl http://www.pnnl.gov http://www.tum.de http://www.hb.se http://WWW.CHEMENGONLINE.COM
Chemical Engineering April 2023

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