Macromolecules,
Год журнала:
2024,
Номер
57(10), С. 4817 - 4825
Опубликована: Май 7, 2024
In
this
study,
polydimethylsiloxane
(PDMS)-based
covalent
adaptable
networks
have
been
prepared
in
a
one-pot,
catalyst-free
way
which
dynamic
β-amino
esters
(BAEs)
are
introduced
via
aza-Michael
addition
between
available
acrylate/amine-terminated
PDMS-compounds.
The
straightforward
introduction
of
those
BAE-groups
such
high-value
elastomers
provides
the
ability
to
relax
applied
stress
at
elevated
temperatures
and
hence
capability
reshaping
by
compression
molding
least
5
times
without
significant
changes
properties.
Moreover,
mechanical
properties
tunable
varying
cross-linker
and/or
filler
content.
Interestingly,
utilization
silica
fillers
not
only
enhances
network
formation
but
also
accelerates
exchange
reactions,
resulting
twice
faster
relaxation
while
maintaining
creep
resistance
service
temperatures.
Chemical Reviews,
Год журнала:
2024,
Номер
124(12), С. 7829 - 7906
Опубликована: Июнь 3, 2024
Covalent
network
polymers,
as
materials
composed
of
atoms
interconnected
by
covalent
bonds
in
a
continuous
network,
are
known
for
their
thermal
and
chemical
stability.
Over
the
past
two
decades,
these
have
undergone
significant
transformations,
gaining
properties
such
malleability,
environmental
responsiveness,
recyclability,
crystallinity,
customizable
porosity,
enabled
development
integration
dynamic
chemistry
(DCvC).
In
this
review,
we
explore
innovative
realm
polymers
focusing
on
recent
advances
achieved
through
application
DCvC.
We
start
examining
history
fundamental
principles
DCvC,
detailing
its
inception
core
concepts
noting
key
role
reversible
bond
formation.
Then
reprocessability
DCvC
is
thoroughly
discussed,
starting
from
milestones
that
marked
evolution
progressing
to
current
trends
applications.
The
influence
crystallinity
then
reviewed,
covering
diversity,
synthesis
techniques,
functionalities.
concluding
section,
address
challenges
faced
field
speculates
potential
future
directions.
Polymer Chemistry,
Год журнала:
2024,
Номер
15(9), С. 815 - 846
Опубликована: Янв. 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.
Science,
Год журнала:
2024,
Номер
383(6682), С. 545 - 551
Опубликована: Фев. 1, 2024
Pluripotency,
which
is
defined
as
a
system
not
fixed
to
its
developmental
potentialities,
typically
associated
with
biology
and
stem
cells.
Inspired
by
this
concept,
we
report
synthetic
polymers
that
act
single
"pluripotent"
feedstock
can
be
differentiated
into
range
of
materials
exhibit
different
mechanical
properties,
from
hard
brittle
soft
extensible.
To
achieve
this,
have
exploited
dynamic
covalent
networks
contain
labile,
thia-Michael
bonds,
whose
extent
bonding
thermally
modulated
retained
through
tempering,
akin
the
process
used
in
metallurgy.
In
addition,
show
shape
memory
behavior
these
tailored
tempering
patterned
spatially
control
properties.
Progress in Polymer Science,
Год журнала:
2024,
Номер
153, С. 101829 - 101829
Опубликована: Май 10, 2024
Liquid
crystal
elastomers
(LCEs)
have
long
held
significant
promise
as
materials
for
artificial
muscles
and
smart
actuators.
Recent
advancements
in
this
field
introduced
innovative
LCE
structures
at
various
scales,
resulting
novel
properties
functionalities
that
further
accentuate
their
actuation
advantages,
bolstering
potential
future
soft
systems.
The
ongoing
pursuit
of
enhanced
performance
functionality
actuators,
essential
advancing
them
towards
superior
material-based
machines
devices,
is
intricately
linked
to
the
understanding
fundamental
structure-property-function
relationships.
This
review
provides
a
perspective
on
these
relationships
across
multiple
structural
levels,
encompassing
chemical
structures,
mesophase
micro-to-macroscale
programmed
structures.
It
delves
into
impact
key
actuation-related
properties,
features,
functionalities.
aspires
provide
valuable
insights
design
high-performance
development
exceptional
modes
behaviors,
expansion
achievable
functionality.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(3), С. 1916 - 1923
Опубликована: Янв. 13, 2023
Convenient
strategies
for
the
deconstruction
and
reprocessing
of
thermosets
could
improve
circularity
these
materials,
but
most
approaches
developed
to
date
do
not
involve
established,
high-performance
engineering
materials.
Here,
we
show
that
bifunctional
silyl
ether,
i.e.,
R'O-SiR2-OR'',
(BSE)-based
comonomers
generate
covalent
adaptable
network
analogues
industrial
thermoset
polydicyclopentadiene
(pDCPD)
through
a
novel
BSE
exchange
process
facilitated
by
low-cost
food-safe
catalyst
octanoic
acid.
Experimental
studies
density
functional
theory
calculations
suggest
an
mechanism
involving
ester
intermediates
with
formation
rates
strongly
depend
on
Si-R2
substituents.
As
result,
pDCPD
manufactured
display
temperature-
time-dependent
stress
relaxation
as
function
their
Moreover,
bulk
remolding
is
enabled
first
time.
Altogether,
this
work
presents
new
approach
toward
installation
exchangeable
bonds
into
commercial
establishes
acid-catalyzed
versatile
addition
toolbox
dynamic
chemistry.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(50), С. 27450 - 27458
Опубликована: Дек. 11, 2023
Upcycling
plastic
waste
into
reprocessable
materials
with
performance-advantaged
properties
would
contribute
to
the
development
of
a
circular
plastics
economy.
Here,
we
modify
branched
polyolefins
and
postconsumer
polyethylene
through
versatile
C–H
functionalization
approach
using
thiosulfonates
as
privileged
radical
group
transfer
functionality.
Cross-linking
functionalized
polytopic
amines
provided
dynamically
cross-linked
polyolefin
networks
enabled
by
associative
bond
exchange
diketoenamine
A
combination
resonant
soft
X-ray
scattering
grazing
incidence
revealed
hierarchical
phase
morphology
in
which
diketoenamine-rich
microdomains
phase-separate
within
amorphous
regions
between
crystallites.
The
dynamic
covalent
cross-links
microphase
separation
results
useful
improved
mechanical
properties,
including
∼4.5-fold
increase
toughness,
reduction
creep
deformation
at
temperatures
relevant
use,
high-temperature
structural
stability
compared
parent
polyolefin.
nature
provides
stress
relaxation
elevated
temperatures,
iterative
reprocessing
polymer
network
little
cycle-to-cycle
property
fade.
ability
convert
thermoformable
material
attractive
thermomechanical
additional
optionality
for
upcycling
enable
future
circularity.
Macromolecules,
Год журнала:
2023,
Номер
56(19), С. 8080 - 8093
Опубликована: Сен. 29, 2023
Vitrimers
are
associative
covalent
adaptable
networks
that
undergo
reversible
bond-exchange
reactions
while
maintaining
a
fixed
cross-linking
density
with
changing
temperature.
To
date,
experimental
studies
rely
on
macroscopic
rheology
have
not
been
able
to
reveal
topological
changes
and
microscopic
dynamics
in
these
materials.
Here,
coarse-grained
molecular
simulations
combined
Monte
Carlo
method
implemented
investigate
the
structural
changes,
dynamics,
linear
of
unentangled
side-chain-linked
vitrimers
conjunction
sticky
Rouse
model
(SRM).
We
find
there
is
minor
variation
structure
The
dynamic
heterogeneities
behavior
system
increase
remarkably
when
approaching
freezing
transition
temperature
Tv.
Quantitative
agreement
between
simulation
results
SRM
predictions
observed
for
stress
relaxation,
elastic
loss
moduli,
relative
mean-squared
displacement,
especially
at
intermediate-
long-time
or
low-frequency
regimes,
where
time–temperature
superposition
principle
satisfied.
obtain
scaling
collapse
curve
bond
relaxation
time,
zero-shear
viscosity,
horizontal
shift
factors
without
introducing
any
parameters,
suggesting
exhibit
similar
even
presence
loop
defects.
Moreover,
good
those
predicted
by
SRM,
indicating
fast
rate
can
be
analyzed
via
single-chain
approach
based
SRM.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(46), С. 25450 - 25462
Опубликована: Ноя. 9, 2023
Finding
new
chemistry
platforms
for
easily
recyclable
polymers
has
become
a
key
challenge
to
face
environmental
concerns
and
the
growing
plastics
demand.
Here,
we
report
dynamic
between
CO2-sourced
alkylidene
oxazolidones
thiols,
delivering
circular
non-isocyanate
polyurethane
networks
embedding
N,S-acetal
bonds.
The
production
of
oxazolidone
monomers
from
CO2
is
facile
scalable
starting
cheap
reagents.
Their
copolymerization
with
polythiol
occurs
under
mild
conditions
in
presence
catalytic
amount
acid
furnish
polymer
networks.
structure
tuned
by
virtue
monomer
design,
translating
into
wide
panel
mechanical
properties
similar
commodity
plastics,
ranging
PDMS-like
elastomers
[with
Young's
modulus
(E)
2.9
MPa
elongation
at
break
(εbreak)
159%]
polystyrene-like
rigid
(with
E
=
2400
MPa,
εbreak
3%).
highly
dissociative
nature
bonds
demonstrated
exploited
offer
three
different
recycling
scenarios
thermosets:
(1)
compression
molding,
extrusion,
or
injection
molding─with
multiple
(at
least
10
times)
without
any
material
property
deterioration,
(2)
chemical
through
depolymerization,
followed
repolymerization,
also
applicable
composites,
(3)
upcycling
two
oxazolidone-based
thermosets
single
one
distinct
properties.
This
work
highlights
platform
designing
containing
elusive
motifs.
versatility
this
shows
great
potential
preparation
materials
(including
composites)
tuneable
structures
properties,
end-of-life
scenarios.
