Macromolecules,
Год журнала:
2024,
Номер
57(21), С. 10098 - 10111
Опубликована: Окт. 30, 2024
Studies
on
structural
and
performance
changes
under
dynamic
loads,
such
as
cyclic
tension,
are
limited.
We
synthesized
a
casting
polyurethane
based
1,5-naphthalene
diisocyanate
with
exceptional
fatigue
resistance,
capable
of
withstanding
up
to
700,000
cycles
flexural
fatigue.
Tensile
tests
were
conducted
at
stretching
strain
amplitude
100%,
frequency
10
Hz,
ranging
from
10,000
100,000
investigate
the
microstructures
properties.
Atomic
force
microscopy
revealed
gradual
decrease
in
high
modulus
region
content,
while
medium
initially
increased
then
decreased,
low
showed
an
increasing
trend.
Transmission
electron
images
clearly
depicted
destruction
process
spherulites:
crystal
bundles
separated
spherulites,
cycles,
these
became
smaller,
eventually
evolving
into
"small
black
dots"
after
cycles.
Wide-angle
small-angle
X-ray
diffraction
analyses
indicated
that
crystallinity,
grain
size,
long
period
transition
layer
thickness
increased.
further
explored
correlation
between
evolution
performance,
elucidating
underlying
mechanisms.
This
study
provides
crucial
insights
polyurethanes
loading,
valuable
for
designing
durable,
fatigue-resistant
materials.
ACS Applied Polymer Materials,
Год журнала:
2024,
Номер
6(5), С. 2604 - 2615
Опубликована: Фев. 19, 2024
Polyurethane
(PU)
foams
are
a
large
volume
commodity
product
and
as
such
pose
considerable
recycling
challenge
for
the
polymer
manufacturing
industry.
The
incorporation
of
dynamic
covalent
bonds
within
PU
network
chemistry
is
possible
strategy
to
improve
sustainable
development
foams.
Herein,
we
report
outcome
research
program
aimed
at
thermoreversible
triazolinedione
(TAD)-indole
linkages
an
industrial
standard
foam
formulation.
A
scalable
synthesis
required
TAD–indole
building
blocks
was
developed,
aiming
maximizing
their
physicochemical
compatibility
with
polyol
isocyanate
ingredients.
pilot
scale
TAD-based
cross-linker
affording
more
than
50
kg
IPDI-derived
bis-urazole
block.
Propoxylation
indole
fragments
proved
be
key
technology
enabling
kilogram
production
based
polyols.
innovative
polyols
were
successfully
used
produce
range
flexible
elastomers
in
solvent-free
Owing
nature
linkers,
could
processed
into
through
thermal
compression
molding,
which
further
recycled
up
7
times
same
manner.
We
studied
effect
compositions
on
foaming
process
efficiency.
mechanical
properties
materials
have
been
analysis,
tensile
measurements,
rheology.
This
work
demonstrates
that
viable
polyurethane
but
also
points
out
some
critical
aspects
obstacles
related
design
Polymers,
Год журнала:
2024,
Номер
16(22), С. 3182 - 3182
Опубликована: Ноя. 15, 2024
Polyurethane
(PU)
foams
are
cellular
polymeric
materials
that
have
attracted
much
attention
across
various
industries
because
of
their
versatile
properties
and
potential
for
multifunctional
applications.
PU
involved
in
many
innovations,
especially
multi-functional
high-performance
Special
is
given
to
developing
tailored
specific
application
needs.
These
applications
including
flame
retardancy,
sound
absorption,
radar
EMI
shielding,
shape
memory,
biomedical
The
increasing
demand
can
perform
multiple
functions
while
maintaining
or
enhancing
core
has
made
a
focal
point
interest
engineers
researchers.
This
paper
examines
the
challenges
faced
by
foam
industry,
particularly
products,
as
well
strategies
improving
sustainability,
such
producing
from
renewable
resources
recycling
existing
materials.
ACS Applied Polymer Materials,
Год журнала:
2024,
Номер
6(10), С. 6183 - 6191
Опубликована: Май 14, 2024
The
thermoset
polyurethane
materials
are
characterized
by
excellent
comprehensive
properties.
However,
the
stable
cross-linked
network
structure
limits
their
reprocessability
and
recyclability.
In
this
study,
a
polybutadiene
polyurethane–urea
material
with
recyclable
reprocessable
properties
was
prepared.
prepared
reacting
isocyanate-capped
prepolymer
curing
agent
2,2′-dithiodianiline
(DTDA
containing
dynamic
disulfide
bonds).
tensile
strength
elongation
at
break
of
were
approximately
21.3
MPa
604%,
respectively.
pieces
underwent
exchange
reaction
in
DTDA/toluene
solution
rapidly
degraded
to
soluble
fragments
(a
series
aniline-terminated
low-molecular-weight
materials)
after
40
min
60
°C.
When
recycled
reacted
isocyanate
compounds,
obtained
again.
exceeded
98%
initial
values.
After
above
degradation–recycling
process
repeated
once
more,
mechanical
second
remained
unchanged.
Additionally,
remolded
being
hot-pressed
150
°C
for
10
produce
high-performance
materials.
This
study
uses
bonds
achieve
degradation,
recovery,
reprocessing
utilization
high-strength
material.
