European Polymer Journal,
Journal Year:
2023,
Volume and Issue:
186, P. 111830 - 111830
Published: Jan. 13, 2023
A
series
of
new
tailored
a-diimine
Ni
(II)
complexes
(Ni-OH,
Ni-FOH,
Ni-PhOH,
and
Ni-PhFOH)
containing
bulky
ortho-N-aryl
groups
with
various
dibenzhydryl
substitutes
was
successfully
synthesized,
characterized
applied
in
ethylene
polymerization.
The
ligands
were
by
1H,
19F,
13C
NMR,
elemental
analysis,
high
resolution
electrospray
ionization
mass
spectrometry
(ESI-HRMS).
X-ray
crystallographic
study
metal
Ni-OH,
Ni-PhFOH
revealed
their
distorted
tetrahedral
geometry.
An
unsymmetrical
steric-enhancement
design
approach
employed
to
modulate
the
competition
between
monomer
insertion
chain-walking
process
This
facile
resulted
a
catalytic
activity
yielded
molecular
weight
PE.
these
optimized
varying
polymerization
conditions
(temperature,
time,
pressure),
use
co-catalysts
variation
Al/Ni
ratio.
When
activated
modified
methylaluminoxane
(MMAO),
exhibited
as
29.1
×
106
g
PE
(mol
Ni)−1
h−1),
1.81
mol−1.
Their
thermal
stability
well
pronounced
at
elevated
temperatures;
2.88
h−1
(0.86
mol−1obtained
90
°C).
PEs
tunable
branches
melting
points
(127.5
°C)
obtained,
which
is
typical
feature
LLDPE.
incorporation
fluorine
atoms
on
N-aryl
had
strong
positive
influence
favored
chain-growth
Surprisingly,
simultaneous
presence
terminal
hydroxyl
group
did
not
adversely
affect
activity,
while
offering
possibility
for
covalent
attachment
solid
supports
future
heterogeneous
Macromolecules,
Journal Year:
2024,
Volume and Issue:
57(3), P. 1080 - 1086
Published: Feb. 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.
Chemical Reviews,
Journal Year:
2024,
Volume and Issue:
124(16), P. 9609 - 9632
Published: July 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.
The Canadian Journal of Chemical Engineering,
Journal Year:
2023,
Volume and Issue:
101(9), P. 4992 - 5019
Published: Jan. 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.
ChemCatChem,
Journal Year:
2024,
Volume and Issue:
unknown
Published: March 26, 2024
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.
Applied Organometallic Chemistry,
Journal Year:
2024,
Volume and Issue:
38(4)
Published: Feb. 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.
