Molecules,
Год журнала:
2025,
Номер
30(8), С. 1847 - 1847
Опубликована: Апрель 20, 2025
The
catalytic
performance
of
α-diiminonickel
complexes
is
highly
sensitive
to
structural
modifications
in
their
ligand
frameworks.
In
this
study,
a
series
unsymmetrical
2,3-bis(arylimino)butane-nickel
featuring
ortho-2,6-dibenzhydryl
groups
as
sterically
demanding
motifs
and
para-methyl
electron-donating
enhancers
were
proposed
synthesized.
These
nickel
thoroughly
characterized
using
FTIR,
elemental
analysis,
single-crystal
X-ray
diffraction
(for
Ni4
Ni5),
revealing
deviations
from
ideal
tetrahedral
geometry.
Upon
activation
with
Et2AlCl,
these
demonstrated
exceptional
ethylene
polymerization
activity,
achieving
remarkable
value
13.67
×
106
g
PE
mol-1
(Ni)
h-1
at
20
°C.
Notably,
even
80
°C,
the
maintained
high
activity
1.97
h-1,
showcasing
superiority
compared
previously
reported
complexes.
resulting
polyethylenes
exhibited
ultra-high
molecular
weights
(Mw:
3.33-19.47
105
mol-1)
tunable
branching
densities
(84-217/1000C),
which
effectively
controlled
by
temperature.
Moreover,
mechanical
properties
polyethylenes,
including
tensile
strength
(σb
=
0.74-16.83
MPa),
elongation
break
(εb
271-475%),
elastic
recovery
(SR
42-74%),
finely
tailored
optimizing
weight,
crystallinity,
degree.
prepared
displayed
outstanding
recovery,
hallmark
high-performance
thermoplastic
elastomers,
making
them
promising
candidates
for
advanced
material
applications.
Chemical Reviews,
Год журнала:
2024,
Номер
124(16), С. 9609 - 9632
Опубликована: Июль 25, 2024
Recycling
mixed
polyolefin
plastics
is
a
significant
challenge
due
to
the
limitations
in
sorting
and
degraded
mechanical
properties
of
blends.
Nonreactive
compatibilization
by
adding
small
amount
polymeric
additive
widespread
approach
restoring
performance
value
recycled
plastics.
Over
past
several
decades,
synthetic
advances
have
enabled
access
low-cost
copolymers
precision
architectures
for
deepening
understanding
mechanisms
semicrystalline
polyolefins.
This
review
covers
design
parameters
compatibilizer,
testing
blends,
methods
producing
economically
viable
additives,
surveys
literature
blends
compatibilized
HDPE,
LLDPE,
LDPE,
iPP.
From
this,
readers
should
gain
comprehension
polymer
mechanics,
synthesis,
macromolecular
engineering
processable
along
with
field's
future
directions.
Macromolecules,
Год журнала:
2024,
Номер
57(3), С. 1080 - 1086
Опубликована: Фев. 1, 2024
Ethylene-based
polyolefin
elastomers
(EPOEs)
represent
a
novel
class
of
material
prepared
using
ethylene
as
the
only
feedstock
and
bear
comparable
mechanical
elastic
properties
versus
traditional
(POEs).
EPOEs
are
from
late-transition-metal
(nickel
or
palladium)-catalyzed
chain
walking
polymerization
ethylene.
However,
literature-reported
potent
catalysts
homogeneous
systems
that
operate
at
relatively
low
temperatures
(<90
°C),
while
industrial
production
POE
materials
requires
high
(>120
°C).
In
this
contribution,
we
install
some
OM
(M
=
H,
Na,
K)
tags
in
an
α-diimine
ligand
framework,
enabling
facile
heterogenization
nickel
complexes
onto
MgCl2-based
solid
support.
The
resulting
heterogeneous
highly
active
demonstrate
much
better
thermal
stability
(up
to
150
°C)
than
their
counterparts.
More
importantly,
polyethylene
products
super-stretchability
2160%)
maintaining
tensile
strength
15.4
MPa)
elasticity
(strain
recovery
value
up
83%).
These
EPOE
can
also
be
used
toughen
polypropylene,
well
compatibilize
blends
polypropylene.
The Canadian Journal of Chemical Engineering,
Год журнала:
2023,
Номер
101(9), С. 4992 - 5019
Опубликована: Янв. 19, 2023
Abstract
Ethylene/α‐olefin
copolymers
are
one
of
the
most
widely‐used
polyolefin
materials.
With
continuous
improvement
catalysts,
high‐performance
materials
were
synthesized
by
adjusting
chain
microstructure,
changing
comonomer
type
and
insertion
amount,
among
which
ethylene/α‐olefin
random
copolymer
elastomer
(POE)
olefin
block
(OBC)
famous
well
accepted
market.
The
excellent
properties
POE
OBC
first
depend
on
their
polymer
microstructure.
microstructure
polyolefins
is
fundamentally
determined
polymerization
conditions,
feed
policies,
reaction
engineering.
High‐performance
elastomers
currently
prepared
high‐temperature
solution
process,
needs
to
be
carried
out
at
a
temperature
above
melting
point
beneficial
speed
up
rate
control
However,
process
launched
more
stringent
requirements
for
coordination
catalyst.
Systematic
reports
catalysts
copolymerization
ethylene
α‐olefins
lacking.
In
this
review,
we
screened
some
suitable
controllable
based
catalyst's
heat
resistance,
activity,
ability,
molecular
weight,
distribution
copolymer,
including
traditional
Z–N
metallocene
post‐metallocene
catalysts.
And
future
development
olefins,
precise
microstructures,
with
polar
monomers
high
envisaged.
Abstract
Recent
progress
regarding
the
copolymerization
of
norbornene
with
various
polar
α‐olefins
catalyzed
by
nickel
and
palladium
catalysts
is
reviewed
here
special
attention
paid
to
diverse
catalyst
frameworks,
monomer
scopes
as
well
polymer
microstructures.
Both
influences
steric
effect
electron
property
ligand
substituents
type
monomers
on
catalytic
behaviors
(activity,
stability,
polarity
tolerance,
etc.)
microstructures
(molecular
weight
distribution,
comonomer
contents,
have
been
summarized.
The
introduction
noncyclic‐olefins,
such
vinyl
monomers,
higher
α‐olefins,
styrenes,
into
rigid
cyclic‐based
polynorbornene
chain
resulted
in
significant
modifications
polarity,
compatibility,
thermostability,
processibility,
transparency,
many
other
properties
material,
which
has
also
discussed
review.
contents
this
review
classified
according
involved
copolymerization,
each
section
included
bearing
different
structures,
will
be
meaningful
for
development
new
types
families
norbornene‐based
cyclic
olefin
copolymer
materials
future.
Angewandte Chemie International Edition,
Год журнала:
2025,
Номер
unknown
Опубликована: Март 6, 2025
Molecular
weight
is
a
crucial
parameter
in
catalytic
olefin
polymerization
to
determine
the
thermomechanical
properties
of
polymers.
Elevating
molecular
ethylene-acrylate
copolymer,
typical
polar
polyolefin
has
been
persistent
challenge.
This
study
presents
direct
synthesis
ultrahigh
(UHMW)
copolymers
using
highly
active,
neutral,
single-component
phosphine-phenolate
nickel
catalyst
under
mild
conditions.
The
coordination-insertion
copolymerization
ethylene
and
various
acrylates,
such
as
methyl
acrylate,
n-butyl
t-butyl
can
yield
with
UHMWs
(Mn)
ranging
from
1000
2700
kDa,
exceptional
activities
up
4.03
×
106
g
mol-1
h-1.
A
relatively
large-scale
(30-50
g)
UHMW
was
notably
achieved.
these
were
comprehensively
evaluated,
demonstrating
that
retained
bulk
polyethylene
(UHMWPE)
while
exhibiting
improved
surface
dyeing
properties.
In
particular,
tensile
strength
significantly
increased
higher
weights,
reaching
44
MPa
(147
after
predrawing
ratio
3.1),
which
comparable
UHMWPE.
Applied Organometallic Chemistry,
Год журнала:
2024,
Номер
38(4)
Опубликована: Фев. 18, 2024
The
properties
and
practical
applications
of
polyethylene
are
closely
associated
with
the
polymer
molecular
weight,
polydispersity,
degree
branching,
type
branches
its
arrangement
within
microstructure.
In
this
study,
a
set
structurally
diverse
unsymmetrical
1‐(2,6‐dibenzhydryl‐4‐hydroxylphenylimino)‐2‐(2,6‐(R)‐4‐(R
1
)phenylimino)acenaphthene‐nickel
dibromide
precatalysts
(where
Ni
2Me
[R
=
Me,
R
H],
2Et
Et,
2iPr
iPr,
3Me
[R,
Me],
2Et,Me
Me])
has
been
prepared
studied
for
ethylene
polymerization.
Molecular
structure
analysis
complexes
revealed
distorted
tetrahedral
geometries
at
nickel.
polymerization
activities
extremely
high
all
upon
activation
either
EASC
or
MMAO
aluminum
reagents,
trend
notably
pronounced
in
case
EASC‐activated
systems,
entering
activity
range
10
million
g
mol
−1
h
30°C.
demonstrated
exceptional
performance
higher
temperatures,
achieving
an
2.4
×
6
100°C
generated
weight
(
M
w
5
)
narrow
dispersity
across
reaction
temperatures
Ð
≈
1.5).
High
temperature
13
C
NMR
spectra
identified
97–142/1000C
resulting
polyethylene,
feature
significantly
dependent
on
temperature.
terms
mechanical
properties,
stress–strain
indicated
that
synthesized
lower
displayed
superior
tensile
strength
compared
produced
while
reverse
was
observed
strain
recovery
analysis.
(up
to
72%)
these
highlights
characteristic
thermoplastic
elastomers.
