Macromolecular Chemistry and Physics,
Journal Year:
2024,
Volume and Issue:
225(13)
Published: March 14, 2024
Abstract
Vitrimer
materials
have
attained
great
interest
owing
to
their
sustainable
functions
and
distinctive
physical
properties.
Compared
with
conventional
cross‐linked
materials,
the
thermoplastic‐like
nature,
such
as
stress
relaxation
creep
at
high
temperatures,
is
outstanding,
which
activation
of
bond
exchange
in
network.
The
temperature
exchange,
so‐called
topology
freezing
(
T
v
),
are
treated
important
material
parameters,
non‐isothermal
(i.e.,
temperature‐ramp)
test
one
method
determine
.
This
study
investigates
effects
network
defects,
that
is,
breaking
point
connectivity,
on
transesterification
vitrimer
samples
varying
fraction
defects
designed
using
thiol‐epoxy
click
reaction,
where
overall
units,
ester
hydroxyl
group,
kept
constant.
Non‐isothermal
tests
conducted
temperature‐ramp
rate
applied
levels,
difference
behaviors
>
discussed
terms
strand
diffusion
during
chain
elongation
under
stress.
Polymer Chemistry,
Journal Year:
2024,
Volume and Issue:
15(9), P. 815 - 846
Published: Jan. 1, 2024
This
tutorial
review
of
linear
viscoelasticity
is
targeted
at
polymer
chemists
working
with
covalent
adaptable
networks.
It
provides
an
overview
concepts,
analysis,
misconceptions,
and
best
practices
for
rheological
experiments.
Polymers,
Journal Year:
2024,
Volume and Issue:
16(10), P. 1373 - 1373
Published: May 11, 2024
Covalent
adaptable
networks
and
vitrimers
are
novel
polymers
with
dynamic
reversible
bond
exchange
reactions
for
crosslinks,
enabling
them
to
modulate
their
properties
between
those
of
thermoplastics
thermosets.
They
have
been
gathering
interest
as
materials
recycling
self-healing
properties.
In
this
review,
we
discuss
different
molecular
simulation
efforts
that
used
over
the
last
decade
investigate
understand
nanoscale
behaviors
covalent
vitrimers.
particular,
dynamics,
Monte
Carlo,
a
hybrid
dynamics
Carlo
approaches
model
reaction,
which
is
main
mechanism
since
it
controls
both
mechanical
rheological
behaviors.
The
techniques
presented
yield
sufficient
results
structure
well
responses
such
networks.
benefits
each
method
highlighted.
use
other
tools
theoretical
models
machine
learning
has
included.
We
noticed,
amongst
most
prominent
results,
stress
relaxes
reaction
happens,
at
temperatures
higher
than
glass
transition
temperature,
better
more
BERs
observed.
lifetime
crosslinks
follows,
moderate
high
temperatures,
an
Arrhenius-like
temperature
dependence.
note
modeling
certain
like
melt
viscosity
topology
freezing
according
behavior
ruled
by
either
Williams–Landel–Ferry
equation
or
Arrhenius
equation.
Discrepancies
in
dissociative
associative
discussed.
conclude
stating
material
parameters
atomistic
factors,
nanoscale,
not
yet
taken
into
account
lacking
current
literature.
Macromolecules,
Journal Year:
2024,
Volume and Issue:
57(17), P. 8621 - 8631
Published: Aug. 23, 2024
Introducing
dynamic
covalent
bonds
in
polymers
is
a
promising
solution
to
improve
their
recyclability
and
self-healing
abilities
minimally
compromising
the
mechanical
properties.
Imine
are
exciting
candidates
as
functionalities
because
of
rapid
exchange
easy
chemical
synthesis.
Although
mechanisms
imines
small
molecules
well-established,
some
misconceptions
still
exist
regarding
behavior
polymers.
Hence,
we
investigate
viscoelastic
properties
imine-bearing
model
systems
highlight
that
imine
bond
only
happens
when
mediated
by
unreacted
amine
groups.
Therefore,
metathesis
unlikely
at
temperatures
below
polymeric
decomposition,
transimination
major
mechanism
exchange.
Surprisingly,
energy
barrier
for
this
depends
on
concentration
functional
groups
forming
bonds.
We
hypothesize
hydrogen
between
aldehyde
might
affect
process,
but
further
work
needed
solve
puzzle.
Advanced Materials,
Journal Year:
2024,
Volume and Issue:
36(28)
Published: April 23, 2024
While
valued
for
their
durability
and
exceptional
performance,
crosslinked
thermosets
are
challenging
to
recycle
reuse.
Here,
inherent
reprocessability
in
industrially
relevant
polyolefin
is
unveiled.
Unlike
prior
methods,
this
approach
eliminates
the
need
introduce
exchangeable
functionality
regenerate
material,
relying
instead
on
preserving
activity
of
metathesis
catalyst
employed
curing
reaction.
Frontal
ring-opening
polymerization
(FROMP)
proves
critical
activity.
Conditions
controlling
catalytic
viability
explored
successfully
reclaim
performance
across
multiple
generations
thus
demonstrating
long-term
reprocessability.
This
straightforward
scalable
remolding
strategy
poised
widespread
adoption.
Given
anticipated
growth
thermosets,
these
findings
represent
an
important
conceptual
advance
pursuit
a
fully
circular
lifecycle
thermoset
polymers.
Macromolecules,
Journal Year:
2024,
Volume and Issue:
57(15), P. 7112 - 7122
Published: July 30, 2024
Continued
progress
in
understanding
the
relaxations
and
mechanical
performance
of
covalent
adaptable
networks
(CANs)
will
lead
to
further
adoption
these
unique
materials
across
a
wide
range
applications.
Using
model
CAN
system
consisting
dynamic,
aromatic
disulfides
epoxy-amine
thermosets,
several
network
characteristics
were
found
vary
as
function
disulfide
concentration
topological
placement.
The
mass
density
was
increase
significantly
with
concentration,
while
glass
transition
temperature
decreased
linearly
content
(from
190
130
°C),
measured
by
modulated
differential
scanning
calorimetry
dynamic
analysis.
Furthermore,
apparent
activation
energy
transition,
Eg,
estimated
time–temperature
superposition,
increasing
concentration.
Significant
changes
sub-Tg
also
observed
correlate
strongly
placement
bonds
within
network.
Macromolecular Materials and Engineering,
Journal Year:
2023,
Volume and Issue:
309(9)
Published: Dec. 24, 2023
Abstract
The
scientific
strategies
reported
in
the
literature
for
developing
biobased
epoxy
vitrimers
are
summarized.
Biomass
resources
such
as
lignin,
cellulose,
or
different
vegetable
oils
can
be
exploited
building
blocks
thermosets
an
alternative
to
bisphenol‐A‐based
ones.
Biorenewable
have
been
synthesized
introducing
dynamic
covalent
bonds
cross‐linked
networks.
This
combination
allows
achieve
networks
with
thermoset‐like
properties
at
a
temperature
of
use,
but
showing
(re)processability,
recyclability,
and
self‐healing
above
well‐defined
named
topology
freezing
transition
(
T
v
).
