ACS Macro Letters,
Год журнала:
2018,
Номер
7(10), С. 1226 - 1231
Опубликована: Сен. 20, 2018
Polymer
networks
that
are
cross-linked
by
dynamic
covalent
bonds
often
sacrifice
the
robust
mechanical
properties
of
traditional
thermosets
in
exchange
for
rapid
and
efficient
reprocessability.
Polyurethanes
attractive
materials
reprocessable
polymers
because
their
excellent
properties,
widespread
use,
ease
synthesis,
but
syntheses
typically
rely
on
harmful
isocyanate
precursors.
Polyhydroxyurethanes
(PHUs),
derived
from
amines
cyclic
carbonates,
promising
alternatives
to
polyurethanes.
PHU
via
transcarbamoylation
reactions
even
absence
external
catalysts,
this
process
occurs
over
hours
at
temperatures
above
150
°C.
We
have
dramatically
shortened
reprocessing
times
incorporating
disulfide
bonds.
Using
cystamine
as
a
comonomer
gives
with
similar
thermal
stability
other
rigid
PHUs.
Despite
these
show
stress
relaxation
characteristic
low
30
s
This
property
enables
quantitative
recovery
cross-link
density
measured
DMTA
after
only
min
elevated-temperature
compression
molding.
Disulfide
incorporation
is
approach
obtain
reprocessable,
resins
not
isocyanates.
Journal of the American Chemical Society,
Год журнала:
2019,
Номер
141(41), С. 16181 - 16196
Опубликована: Сен. 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,
Год журнала:
2019,
Номер
10(45), С. 6091 - 6108
Опубликована: Янв. 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.
ACS Sustainable Chemistry & Engineering,
Год журнала:
2018,
Номер
6(9), С. 11145 - 11159
Опубликована: Авг. 26, 2018
Cross-linked
polymers
are
ubiquitous
in
daily
life,
finding
applications
as
tires,
insulation,
adhesives,
automotive
parts,
and
countless
other
products.
The
covalent
cross-links
these
materials
render
them
mechanically
robust,
chemically
resistant,
thermally
stable,
but
they
also
prevent
recycling
of
into
similar-value
goods.
Furthermore,
cross-linked
typically
produced
from
petroleum-based
feedstocks,
their
hydrocarbon
backbones
nondegradable,
making
unsustainable
the
long
term.
In
recent
years,
much
effort
has
focused
on
development
strategies
for
polymeric
materials.
following
Perspective,
we
discuss
many
approaches,
highlight
efforts
to
sustainably
produce
recyclable
polymers.
We
present
our
thoughts
future
challenges
that
must
be
overcome
enable
widespread,
viable,
more
sustainable
practical
implementation
materials,
including
sourcing
long-term
environmental
stability
inherently
dynamic
polymers,
moving
toward
industrially
viable
synthesis
reprocessing
methods.
Advanced Materials,
Год журнала:
2020,
Номер
32(20)
Опубликована: Фев. 14, 2020
Abstract
Covalent
adaptable
networks
(CANs),
unlike
typical
thermosets
or
other
covalently
crosslinked
networks,
possess
a
unique,
often
dormant
ability
to
activate
one
more
forms
of
stimuli‐responsive,
dynamic
covalent
chemistries
as
means
transition
their
behavior
from
that
viscoelastic
solid
material
with
fluid‐like
plastic
flow.
Upon
application
stimulus,
such
light
irradiation,
temperature,
even
distinct
chemical
signal,
the
CAN
responds
by
transforming
state
temporal
plasticity
through
activation
either
reversible
addition
bond
exchange,
which
allows
essentially
re‐equilibrate
an
altered
set
conditions
are
those
in
original
network
is
formed,
simultaneously
enabling
new
and
shape,
function,
characteristics.
As
such,
CANs
span
divide
between
thermoplastics,
thus
offering
unprecedented
possibilities
for
innovation
polymer
materials
science.
Without
attempting
comprehensively
review
literature,
recent
developments
discussed
here
emphasis
on
most
effective
render
these
be
stimuli
responsive,
features
make
broadly
applicable.
Journal of the American Chemical Society,
Год журнала:
2018,
Номер
140(20), С. 6217 - 6220
Опубликована: Май 7, 2018
Traditional
thermoset
materials
have
favorable
material
properties
but
are
unable
to
reprocess
and
difficult
recycle.
Small
molecule
boroxines
been
shown
undergo
a
reversible
exchange
reaction.
Herein
we
employ
boroxine
as
dynamic
cross-links
construct
novel
type
of
that
is
strong,
highly
malleable,
recyclable.
The
synthesis
mechanical
networks
described.
Upon
heating
in
water
the
can
be
recycled
back
its
monomer.
With
multitude
tunable
variables,
anticipate
this
system
platform
for
development
range
new
materials.
Materials & Design,
Год журнала:
2019,
Номер
186, С. 108248 - 108248
Опубликована: Ноя. 12, 2019
Vitrimers
are
a
new
type
of
polymers
with
promising
applications
in
innovative
materials.
Epoxidized
soybean
oil
(ESO)
is
an
ideal
candidate
for
vitrimer
preparation
owing
to
its
abundant
epoxy
groups.
However,
preparing
plant
oil-based
vitrimers
high
glass
transition
temperatures
(Tg)
and
strength
remains
challenging.
A
novel
fully
bio-based
Tg
above
room
temperature
was
synthesized
from
ESO
rosin
derivative-fumaropimaric
acid
(FPA)
exhibited
excellent
self-healing,
shape
memory,
reprocessing
due
the
presence
dynamic
covalent
bond
exchange.
The
ESO-FPA
65
°C
tensile
16
MPa,
which
resulted
rigid
structure
tricarboxylic
groups
FPA.
effect
transesterification
reactions
on
network
confirmed
through
stress
relaxation.
Our
work
expands
commercial
materials
provides
approach
prepare
desirable
properties.
