ACS Sustainable Chemistry & Engineering,
Год журнала:
2024,
Номер
12(18), С. 7126 - 7135
Опубликована: Апрель 24, 2024
Improving
the
sustainability
of
thermosets
is
a
crucial
challenge
in
polymer
science
due
to
overdependence
on
petrochemical-based
feedstocks
and
their
infusible
cross-linked
networks,
which
limit
reprocessing
after
use.
Implementing
renewable
recyclability
production
networks
paves
way
for
development
next-generation
sustainable
materials.
Polybenzoxazines
(PBzs)
provide
superior
alternative
traditional
phenolic
resin,
with
opportunities
incorporation
dynamic
linkages
owing
high
molecular
design
flexibility,
endowing
reprocessability.
Incorporating
sulfide
bonds
PBz
can
produce
smart
functionalities
reversible
bond
exchange
mechanism,
may
unique
solution
address
issue
end-of-life
by
enabling
processability.
The
present
work
employs
biobased
cardanol-cystamine
industrial
byproduct
sulfur
construct
reusable
thermoset
poly(benzoxazine-random-sulfur)
intrinsic
undergoing
dual
(associative
dissociative)
mechanisms.
copolymer
showed
recycling
(R),
reshaping
self-healing
(S),
shape
recovery
(S)
was
explored
as
load-bearing
flexible
film
debondable
adhesive
features
showcasing
appreciable
mechanical
strength.
flexibility
reprocessability
synthesized
copolymers
will
benefit
quest
benign
polymers
serving
wide
arena
applications.
Macromolecules,
Год журнала:
2024,
Номер
57(7), С. 3242 - 3257
Опубликована: Март 28, 2024
We
formulate
a
statistical
mechanical
theory
for
how
dynamic
bond
exchange
influences
the
activated
hopping-driven
relaxation
of
Kuhn
segments
in
dynamically
cross-linked
networks
or
vitrimers
over
wide
range
temperatures
and
cross-link
densities.
The
key
new
methodological
aspect
is
to
address
self-consistent
manner
consequences
on
segmental
alpha
relaxation,
vice
versa.
predicted
temperature
dependence
time
at
high
remains
same
as
that
permanent
networks,
but
lower
temperatures,
significant
acceleration
occurs
due
exchanges.
From
mechanistic
perspective,
vitrimer
local
cage
barrier
very
weakly
affected
by
exchange,
while
collective
elastic
contribution
decreases
significantly
deeply
supercooled
regime.
glass
transition
grow
linearly
with
square
root
density,
previously
found
networks.
Material-specific
chemical
effects
such
cross-linker
size
relative
normal
segment
special
attraction
polymers
are
crudely
considered
based
model
calculations.
quantitatively
applied
recent
experiments
dry
ethylene
vitrimers.
Good
agreements
including
follows
an
Arrhenius
law
enough
upward
non-Arrhenius
deviations
emerge
regime,
collapsed
master
curve
exists
densities
temperatures.
Possible
extensions
treat
heterogeneity
penetrant
transport
briefly
discussed.
Molecules,
Год журнала:
2024,
Номер
29(14), С. 3261 - 3261
Опубликована: Июль 10, 2024
Dynamic
bonds
can
facilitate
reversible
formation
and
dissociation
of
connections
in
response
to
external
stimuli,
endowing
materials
with
shape
memory
self-healing
capabilities.
Temperature
is
an
stimulus
that
be
easily
controlled
through
heat.
covalent
temperature
reversibly
connect,
exchange,
convert
chains
the
polymer.
In
this
review,
we
introduce
dynamic
operate
without
catalysts
various
ranges.
The
basic
bonding
mechanism
kinetics
are
examined
understand
chemistry
performed
by
equilibrium
control.
Furthermore,
a
recent
synthesis
method
implements
coupling
based
on
polymers
introduced.
depending
applied
expand
use
polymers,
providing
predictions
for
development
future
smart
materials.
Chemical Science,
Год журнала:
2024,
Номер
15(19), С. 7061 - 7071
Опубликована: Янв. 1, 2024
Acid-base
catalysis
is
a
common
strategy
to
induce
covalent
bond
exchanges
in
dynamic
polymer
networks.
Strong
acids
or
strong
bases
can
promote
rapid
network
rearrangements,
and
are
simultaneously
preferred
catalysts
for
chemical
reactions
where
maximum
efficiency
at
the
lowest
possible
temperature
aimed
for.
However,
within
context
of
networks,
incorporation
highly
active
negatively
affect
longer
term
application
potential.
Network
dynamicity
diminish
through
catalyst
ageing
quenching
may
prematurely
activate
exchanges,
leading
dimensional
instability
thus
low
creep
resistance
Herein,
we
present
several
examples
explicitly
explored
weak
(carboxylic
acids)
as
using
vinylogous
urethanes
(VU)
well-understood
protic
acid
catalysed
vitrimer
chemistry.
Surprisingly,
have
found
that
sought-after
long-term
stability
offered
by
does
not
necessarily
bring
lower
activity
high
temperature.
In
fact,
show
remarkable
thermoswitchable
catalytic
behaviour,
going
from
an
inactive
hydrogen
bonded
state
matrix
protonated,
with
profound
impact
on
reactivity
rheology.
Carboxylic
different
electronic
steric
environments
clear
trends
their
fine-tuning
resulted
most
thermally
responsive
VU
vitrimers
studied
date.
Our
findings
point
out
choice
design
only
poorly
informed
performance
more
traditional
(in
solvent),
tailored
holds
great
promise
field
vitrimers.
Soft Matter,
Год журнала:
2023,
Номер
19(16), С. 2857 - 2877
Опубликована: Янв. 1, 2023
In
this
review
we
highlight
the
underlying
mechanisms
of
phase
separation
in
dynamic
polymer
networks,
distinguishing
between
supramolecular
networks
and
covalent
adaptable
discuss
effect
on
material
properties.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(26), С. 14427 - 14434
Опубликована: Июнь 23, 2023
Although
the
catalyst-free
dynamic
thia-Michael
(tM)
reaction
has
been
leveraged
for
a
range
of
significant
applications
in
materials
science
and
pharmaceutical
development,
exploiting
its
full
potential
limited
by
relatively
low
equilibrium
constants.
To
address
this
shortcoming,
new
series
catalyst-free,
room-temperature
acceptors
bearing
an
isoxazolone
motif
were
developed
utilized
to
access
both
covalent
networks
linear
polymers.
By
leveraging
generation
aromaticity
upon
thiol
addition
tuning
electronic-withdrawing/donating
nature
acceptor
at
two
different
sites,
wide
constants
(Keq
∼1000
∼100,000
M-1)
obtained,
constituting
2
orders
magnitude
increase
compared
their
noncyclic
benzalcyanoacetate
analogues.
Integration
into
ditopic
isoxazolone-based
Michael
allowed
bulk
polymers;
these
not
only
exhibited
tailorable
thermomechanical
properties
based
on
composition,
but
higher
Keq
tM
bonds
resulted
more
mechanically
robust
relative
past
designs.
Furthermore,
solution-state
formation
polymers
was
achieved
thanks
increased
acceptors.
Abstract
Vitrimers
are
an
innovative
class
of
polymers
that
boast
a
remarkable
fusion
mechanical
and
dynamic
features,
complemented
by
the
added
benefit
end‐of‐life
recyclability.
This
extraordinary
blend
properties
makes
them
highly
attractive
for
variety
applications,
such
as
automotive
sector,
soft
robotics,
aerospace
industry.
At
their
core,
vitrimer
materials
consist
crosslinked
covalent
networks
have
ability
to
dynamically
reorganize
in
response
external
factors,
including
temperature
changes,
pressure
variations,
or
shifts
pH
levels.
In
this
review,
aim
is
delve
into
latest
advancements
theoretical
understanding
computational
design
vitrimers.
The
review
begins
offering
overview
fundamental
principles
underlie
behavior
these
materials,
encompassing
structures,
behavior,
reaction
mechanisms.
Subsequently,
recent
progress
vitrimers
explored,
with
focus
on
employment
molecular
dynamics
(MD)/Monte
Carlo
(MC)
simulations
density
functional
theory
(DFT)
calculations.
Last,
existing
challenges
prospective
directions
field
critically
analyzed,
emphasizing
necessity
additional
advancements,
coupled
experimental
validation.
Macromolecules,
Год журнала:
2023,
Номер
56(17), С. 6978 - 6987
Опубликована: Авг. 27, 2023
Polyurethane
(PU)
thermosets
are
usually
landfilled
at
the
end
of
their
service
lifetimes
and
cannot
be
recycled
through
conventional
means.
Although
dibutyltin
dilaurate
(DBTDL)
is
an
effective
catalyst
for
reprocessing
PU
thermosets,
organotins
immunotoxic
teratogenic,
which
concerning
catalysts
embedded
within
covalent
adaptable
networks
(CANs).
Here,
we
identify
Zr(acac)4
Zr(tmhd)4
as
to
reprocess
CANs
more
sustainably.
Thermoset
foams
containing
Zr-based
exhibit
characteristic
stress
relaxation
times
between
6
200
s,
similar
or
faster
than
DBTDL.
These
capable
a
foam
four
five
cycles.
Dynamic
mechanical
thermal
analysis
indicates
that
zirconium-based
preserve
glass
transition
temperature
crosslink
density
cycles
promising
bulk
thermoset
PUs.
Furthermore,
solvent-free
method
was
developed
by
co-milling
Zr
catalyst.
Ultimately,
these
methods
using
will
impart
greater
sustainability
circularity
plastics.
ACS Applied Polymer Materials,
Год журнала:
2023,
Номер
5(6), С. 3971 - 3978
Опубликована: Май 8, 2023
A
mechanically
interlocked
vitrimer
(MIV)
based
on
a
benzoxazine
monomer
and
polyrotaxane
(PR)
has
been
prepared
through
network
(MIN)
dynamic
covalent
bond
chemistry.
The
transacetalation
exchange
the
N,O-acetal-type
polybenzoxazine
(PBz)
structure
was
catalyzed
by
tin
compound.
Compared
to
controlled
PBz
without
MIN,
designed
MIV
shows
enhanced
mechanical
performance
including
ductility
tensile
strength
while
maintaining
relatively
high
Young's
modulus
glass
transition
temperature
(Tg).
can
be
reprocessed
several
times
compromising
thermal
stability.
also
exhibits
faster
lower
activation
energy
compared
due
mobile
intramolecular
motions
of
PR
in
allowing
for
more
readily.
usefulness
present
study
preparation
high-performance
eco-friendly
thermosetting
vitrimers
is
discussed.
Advanced Functional Materials,
Год журнала:
2024,
Номер
34(46)
Опубликована: Июль 18, 2024
Abstract
Ion‐conductive
elastomers
capable
of
damping
can
significantly
mitigate
the
interference
caused
by
mechanical
noise
during
data
acquisition
in
wearable
and
biomedical
devices.
However,
currently
available
often
lack
robust
properties
have
a
narrow
temperature
range
for
effective
damping.
Here,
precise
modulation
weak
to
strong
ion‐dipole
interactions
plays
crucial
role
bolstering
network
stability
tuning
relaxation
behavior
supramolecular
ion‐conductive
(SICEs).
The
SICEs
exhibit
impressive
properties,
including
modulus
13.2
MPa,
toughness
65.6
MJ
m
−3
,
fracture
energy
74.9
kJ
−2
.
Additionally,
they
demonstrate
remarkable
capabilities,
with
capacity
91.2%
peak
tan
δ
1.11.
Furthermore,
entropy‐driven
rearrangement
ensures
SICE
remain
stable
even
at
elevated
temperatures
(18–200
°C,
>
0.3),
making
it
most
thermally
resistant
elastomer
reported
date.
Moreover,
proves
filtering
out
various
noises
physiological
signal
detection
strain
sensing,
highlighting
its
vast
potential
flexible
electronics.