A
series
of
vitrimers
combining
dynamic
hydrogen
and
imine
bonds
was
prepared
by
a
reaction
between
amine-terminated
nonisocyanate
polyurea
oligomers
(NIPUrea),
terephthalaldehyde,
tris(2-aminoethyl)amine
at
various
equivalent
ratios.
NIPUrea
different
molecular
weights
were
using
an
environmentally
friendly
sustainable
approach,
implying
transurethane
polycondensation
technology.
The
possessed
cross-linking
densities
exhibited
Tg
values
around
20
°C,
as
well
thermal
stabilities
exceeding
300
°C.
They
displayed
high
tunable
mechanical
strength
ductility,
with
Young's
modulus
from
1.7
to
26.4
MPa,
breaking
stress
7.9
12.9
MPa
elongation
break
147
517%.
revealed
good
solvent
resistance
except
in
acidic
THF/water
solutions,
which
they
underwent
irreversible
degradation
solubilization.
Most
the
materials
excellent
self-healing
efficiency
room
temperature
(93
107%)
reprocessability
recyclability
after
hot
pressing.
Macromolecules,
Год журнала:
2025,
Номер
58(4), С. 1923 - 1934
Опубликована: Фев. 5, 2025
Developing
closed-loop
recyclable
thermosets
and
understanding
their
structure–property
relationships
are
essential
steps
in
advancing
a
circular
materials
economy.
Here,
we
present
vinylogous
urethane
(VU)
thermoset
with
recyclability,
synthesized
through
the
reaction
of
polytetrahydrofuran
bisacetoacetate
(aPTHF)
tris(2-aminoethyl)amine
(TREN).
These
VU
polymers
exhibit
high
elasticity,
only
3–9%
residual
strain
observed
after
cyclic
tensile
testing
at
maximum
100%,
depending
on
molecular
weight
aPTHF
network
cross-link
density.
The
two
structural
parameters
also
allow
modulation
mechanical
stress-relaxation
properties
elastomers.
To
investigate
hydrolysis
linkages
within
hydrophobic
matrix,
employed
heterogeneous
system
using
biphasic
mixture
HCl
CDCl3.
Our
findings
show
that
VUs
remain
stable
pure
water
but
can
be
dissociated
under
acidic
conditions,
dissociation
rate
accelerated
higher
temperatures
and/or
presence
concentrations.
detailed
investigations
indicate
potential
elastomers
as
sustainable
substrates
for
wearable
sensors.
We
therefore
conduct
case
study
synthesizing
sensor
incorporation
multiwalled
carbon
nanotubes
(MCNs)
into
elastomer
matrix.
robustly
detect
various
movements.
Moreover,
treatment
both
neat
polymer
composite
diethyl
ether
solvent
allows
excellent
recovery
(>90%)
TREN
(86%),
without
discernible
damage
to
MCNs
reclaimed
from
latter.
Advanced Functional Materials,
Год журнала:
2024,
Номер
unknown
Опубликована: Сен. 27, 2024
Abstract
The
increasing
market
demand
for
flexible
polyurethane
foams
(PUFs)
is
prompting
the
academic
and
industrial
community
to
seek
solutions
their
end‐of‐life
management.
In
this
study,
issue
addressed
by
incorporating
β‐amino
ester
(BAE)
moieties
into
foam
structure.
This
addition
results
in
hybrid
PU‐BAE
that
can
be
thermally
reprocessed
chemically
recycled,
with
cell
sizes
ranging
from
780
990
µm
densities
between
90
150
kg
m
−3
.
These
demonstrate
thermomechanical
reprocessability,
yielding
stable
elastomers,
glass
transition
temperature
values
14
25
°C.
Stress
relaxation
experiments
reveal
remarkably
fast
times
these
elastomers
(23
s
at
160
°C).
Furthermore,
a
systematic
investigation
of
chemical
recyclability
via
glycosylation
conducted
under
mild
conditions,
achieving
complete
disintegration
within
20
min
65
Finally,
recycled
product
converted
again,
closed
loop
foam‐to‐foam
recycling
process.
findings
indicate
integration
BAE
PUFs
leads
an
enhanced
rate,
providing
promising
avenue
addressing
concerns
PUF‐applications.
Macromolecules,
Год журнала:
2024,
Номер
57(9), С. 4246 - 4253
Опубликована: Апрель 26, 2024
Vitrimers
are
covalently
cross-linked
polymers
that
can
be
reshaped
and
recycled,
triggered
by
the
temperature.
Well
above
canonical
glass
transition
temperature
Tg,
they
gain
malleable,
thermoplastic-like
properties;
below,
behave
as
thermosets.
The
responsible
molecular
mechanism
is
enabled
dynamic
covalent
bond
exchange.
However,
underlying
physics
of
from
thermoplastic
to
thermoset
properties
rather
unclear
subject
current
scientific
debate.
In
this
work,
we
address
questions
what
extent
temperature-dependent
malleability
vitrimers
reflected
in
thermal
expansion
behavior
and,
conversely,
suited
characterize
respective
creep
vitrimers.
It
will
shown
at
least
case
used
model
vitrimer,
only
able
stop
vitrimer
undergo
irreversible
shape
changes
often-discussed
topology
freezing
Tv
purely
operational.
ACS Applied Polymer Materials,
Год журнала:
2024,
Номер
6(17), С. 10718 - 10726
Опубликована: Авг. 22, 2024
The
development
of
click
polymerization
toward
the
creation
structurally
diverse
closed-loop
recyclable
polymers
is
challenging
yet
desirable
in
modern
polymer
chemistry.
In
this
work,
we
report
a
modular
amino-acetoacetate
polymerization,
which
proceeds
under
mild
conditions
and
produces
H2O
as
only
byproduct.
Through
systematic
optimization
reaction
parameters,
successfully
synthesized
22
poly(vinylogous
urethane)s
possessing
high
molecular
weights
(Mw
up
to
93.7
kDa)
well-defined
structures
outstanding
yields
(up
98%).
diacetoacetate
monomers
are
derived
from
diols,
both
diols
diamine
common
chemicals
that
can
be
produced
renewable
biomass.
Notably,
these
exhibit
ability
depolymerize
back
their
respective
conditions,
highlighting
excellent
recyclability.
This
enables
synthesis
with
structures,
providing
versatile
platform
for
fabrication
materials
such
plastics,
elastomers,
carbon
fiber-reinforced
composites.
methodology
material
innovations
discussed
work
may
benefit
promotion
application
greatly
demands
scenarios.
Macromolecular Rapid Communications,
Год журнала:
2024,
Номер
unknown
Опубликована: Ноя. 13, 2024
Aromatic
esters
are
amongst
the
oldest
known
chemical
motifs
that
allow
for
thermal
(re)processing
of
thermosetting
polymers.
Moreover,
phenyl
generally
as
activated
do
not
require
a
catalyst
to
undergo
acyl
transfer
reactions.
Even
though
dynamic
aromatic
find
applications
in
commercialized
thermoset
formulations,
all-aromatic
have
found
limited
use
so
far
design
covalent
adaptable
networks
(CAN)
result
their
high
glass
transition
temperature
(T
