Macromolecules,
Journal Year:
2021,
Volume and Issue:
54(10), P. 4782 - 4791
Published: May 5, 2021
Model
polydimethylsiloxane
telechelic
vitrimers
with
dynamic
boronic
ester
bonds
were
synthesized
to
investigate
the
viscoelastic
properties
of
networks
extremely
low
Tg
via
multiple
rheological
approaches.
Frequency
sweeps
and
stress
relaxation
tests,
conducted
at
more
than
120
°C
above
Tg,
show
anticipated
Arrhenius
behavior
time
inverse
temperature
give
same
activation
energy
for
a
fixed
molecular
weight,
obtained
using
variety
analysis
methods.
Time–temperature
superposition
demonstrates
that
flow
regime
is
thermorheologically
simple,
while
modulus
plateau
increases
increasing
temperature,
consistent
conserved
network
topology
associative
bond
exchange.
As
times
decrease,
rubbery
increases,
indicating
decoupling
terminal
dynamics
from
mechanics.
Below
40
°C,
second
lower
emerges,
which
attributed
transition
dominated
by
reaction
exchange
kinetics
dictated
local
polymer
dynamics.
Our
work
points
importance
assessing
broad
window
approaches
in
probing
networks.
Journal of the American Chemical Society,
Journal Year:
2019,
Volume and Issue:
141(41), P. 16181 - 16196
Published: Sept. 16, 2019
The
classical
division
of
polymeric
materials
into
thermoplastics
and
thermosets
based
on
covalent
network
structure
often
implies
that
these
categories
are
distinct
irreconcilable.
Yet,
the
past
two
decades
have
seen
extensive
development
bridge
this
gap
through
incorporation
dynamic
crosslinks,
enabling
them
to
behave
as
both
robust
networks
moldable
plastics.
Although
their
potential
utility
is
significant,
growth
adaptable
(CANs)
has
obscured
line
between
"thermoplastic"
"thermoset"
erected
a
conceptual
barrier
growing
number
new
researchers
entering
discipline.
This
Perspective
aims
outline
fundamental
theory
CANs
provide
critical
assessment
current
status.
We
emphasize
throughout
unique
properties
emerge
from
chemistry,
particularly
highlight
role
crosslink
exchange
mechanism
(i.e.,
dissociative
or
associative
exchange)
plays
in
resultant
material
under
processing
conditions.
Predominant
focus
will
be
thermally
induced
behavior,
majority
presently
employed
chemistries
rely
thermal
stimulus,
it
simple
apply
bulk
materials.
Lastly,
identify
issues
address
possible
solutions
for
better
understanding
within
field.
Polymer Chemistry,
Journal Year:
2019,
Volume and Issue:
10(45), P. 6091 - 6108
Published: Jan. 1, 2019
A
selection
of
dynamic
chemistries
is
highlighted,
with
a
focus
on
the
reaction
mechanisms
molecular
network
rearrangements,
and
how
mechanistic
profiles
can
be
related
to
mechanical
physicochemical
properties
polymer
materials.
Chemical Science,
Journal Year:
2020,
Volume and Issue:
11(19), P. 4855 - 4870
Published: Jan. 1, 2020
In
this
minireview,
we
survey
recent
advances
in
the
development
of
vitrimer
materials.
Focus
on
how
to
chemically
control
their
material
properties
is
used
highlight
challenges
for
boosting
potential
emerging
class
polymer
Macromolecules,
Journal Year:
2019,
Volume and Issue:
52(5), P. 2105 - 2111
Published: Feb. 20, 2019
Cross-linked
networks
feature
exceptional
chemical
and
mechanical
resilience
but
consequently
lack
recyclability.
Vitrimers
have
emerged
as
a
class
of
materials
that
the
robustness
thermosets
recyclability
thermoplastics
without
compromising
network
integrity.
Most
examples
vitrimers
involved
new
polymers
with
exchangeable
bonds
within
their
backbones.
In
pursuit
more
universal,
commercially
viable
route,
we
propose
method
utilizing
available
inexpensive
reagents
to
prepare
from
vinyl
monomer-derived
prepolymers
contain
cross-linkable
β-ketoester
functional
groups.
Controlled
radical
copolymerization
methyl
methracrylate
(2-acetoacetoxy)ethyl
methacrylate
afforded
linear
were
converted
into
in
single
step
by
treatment
trifunctional
amine.
These
displayed
characteristic
features
reprocessability
over
many
six
(re)processing
cycles.
Critically,
prepared
through
this
process
largely
retain
thermal
properties
counterparts,
suggesting
holds
significant
utility
user-friendly
relevant
approach
rational
design
diverse
properties.
Journal of the American Chemical Society,
Journal Year:
2019,
Volume and Issue:
141(38), P. 15277 - 15287
Published: Aug. 30, 2019
Covalent
adaptable
networks
(CANs)
often
make
use
of
highly
active
external
catalysts
to
provide
swift
exchange
the
dynamic
chemical
bonds.
Alternatively,
milder
species
can
act
as
internal
when
covalently
attached
matrix
and
in
close
proximity
In
this
context,
we
introduce
phthalate
monoesters
a
novel
chemistry
platform
for
covalent
networks.
A
low-molecular-weight
(MW)
model
study
shows
that
these
undergo
fast
transesterification
via
dissociative
mechanism,
caused
by
catalysis
free
carboxylic
acid,
which
reversibly
forms
an
activated
phthalic
anhydride
intermediate.
Using
chemistry,
wide
series
CANs
with
broad
range
properties
have
been
prepared
simply
curing
mixture
diols
triols
bifunctional
anhydrides.
The
nature
was
confirmed
recycling
experiments
multiple
cycles
stress
relaxation
using
rheology.
proved
be
resistant
deformation
but
showed
marked
temperature
response
their
rheological
behavior,
related
reactions
high
activation
energy
(120
kJ/mol).
While
densely
cross-linked
hydrolytically
stable
polyester
low
soluble
fractions
obtained,
found
that,
swelling
hot
solvent,
gel-to-sol
transition
happened,
resulted
full
dissolution
network.
Green Chemistry,
Journal Year:
2019,
Volume and Issue:
21(7), P. 1596 - 1601
Published: Jan. 1, 2019
A
bio-based
polyimine
vitrimer
containing
100%
renewable
carbon
content
has
been
synthesised
and
characterised,
based
on
furan
dialdehyde
derived
from
fructose.
Journal of the American Chemical Society,
Journal Year:
2019,
Volume and Issue:
142(1), P. 283 - 289
Published: Dec. 3, 2019
In
this
report,
we
merge
block
copolymers
with
vitrimers
in
an
effort
to
realize
the
prospect
of
higher-order,
nanoscale
control
over
associative
cross-link
exchange
and
flow.
We
show
use
controlled
polymerization
as
a
vital
tool
understand
fundamental
structure–property
effects
through
precise
polymer
architecture
molecular
weight.
Vitrimers
derived
from
self-assembling
exhibit
superior
resistance
macroscopic
deformation
comparison
their
analogs
generated
statistical
copolymers.
Our
results
suggest
that
enhanced
creep
achieved
by
chain
topology
can
be
used
tune
viscoelastic
properties.
The
arises
microphase-separated
structure
new
class
materials
differentiates
counterparts
introduces
potential
topology-control
Materials Horizons,
Journal Year:
2019,
Volume and Issue:
7(1), P. 104 - 110
Published: Aug. 23, 2019
This
study
describes
a
rational
approach
to
go
beyond
the
current
processability
limits
of
vitrimer
materials,
with
demonstration
low-viscosity
fast
processing
highly
crosslinked
permanent
networks.
