Macromolecules,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Dec. 25, 2024
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.
The
preparation
of
foams
with
self-healing
properties
and
stable
cell
structures
continues
to
present
significant
challenges.
In
this
study,
a
polydimethylsiloxane
elastomer
featuring
dual
network
structure
was
developed.
A
dynamic
cross-linking
network,
formed
by
hydrogen
disulfide
bonds,
imparted
capabilities
the
elastomer.
inclusion
agent
created
an
inherent
that
improved
mechanical
melt
strength
synthesized
demonstrated
exceptional
performance,
achieving
efficiency
92.89%,
along
impressive
properties,
including
tensile
6.32
MPa
elongation
at
break
1277.80%.
Additionally,
foam
fabricated
using
supercritical
carbon
dioxide
(sc-CO2)
foaming
method.
With
increase
in
cross-linking,
size
decreased
from
11.88
8.60
μm,
while
density
increased
2.04
×
109
2.71
cells/cm3,
resulting
uniform
distribution
within
foam.
Microcracks
were
effectively
healed
10
min
80
°C,
morphology
remained
after
96
h
exposure
environmental
conditions.
This
dual-network
exhibited
excellent
performance
structure.
