Multicentered self-immobilized ethylene polymerization catalysts based on functionalized titanium halide salicylaldiminate complexes for the synthesis of ultra-high-molecular-weight polyethylene

Article abstract of DOI:10.1134/S1070427212090170

Specifi c features of ethylene polymerization using a new group of catalytic systems based on ten methylalumoxane-activated titanium halide salicylaldiminato complexes functionalized with ?-vinylalkoxy groups and containing tert-butyl substituents in the phenoxide moiety were studied. The catalytic activity of the new group of activated complexes is strongly affected by the position of the ?-vinylalkoxy functional group and by the number and position of substituents in the phenoxide moiety. These factors determine the ratio of the homogeneous and heterogeneous steps of the polymerization as a result of the catalyst self-immobilization onto the polymer formed, and also the molecular characteristics of the polymer obtained at 20, 40, and 60°C and ethylene pressure of 0.4 MPa. The possibility and conditions of preparing ultra-high-molecular-weight polyethylene with improved morphology were revealed. Pleiades Publishing, Ltd., 2012.

Full text of DOI:10.1134/S1070427212090170

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2012, Vol. 85, No. 9, pp. 1404−1412. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © N.I. Ivancheva, S.Ya. Khaikin, E.V. Sviridova, S.P. Fedorov, D.V. Sanieva, O.V. Molev, I.V. Oleinik, S.S. Ivanchev, 2012, published in
Zhurnal Prikladnoi Khimii, 2012, Vol. 85, No. 9, pp. 1493−1501.
MACROMOLECULAR COMPOUNDS
AND POLYMERIC MATERIALS
Multicentered Self-Immobilized Ethylene Polymerization
Catalysts Based on Functionalized Titanium Halide
Salicylaldiminate Complexes for the Synthesis
of Ultra-High-Molecular-Weight Polyethylene
N. I. Ivancheva, S. Ya. Khaikin, E. V. Sviridova, S. P. Fedorov, D. V. Sanieva,
O. V. Molev, I. V. Oleinik, and S. S. Ivanchev
St. Petersburg Branch, Boreskov Institute of Catalysts, Siberian Branch,
Russian Academy of Sciences, St. Petersburg, Russia
Vorozhtsov Novosibirsk Institute, of Organic Chemistry,
Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Received August 24, 2012
Abstract—Specific features of ethylene polymerization using a new group of catalytic systems based on ten
methylalumoxane-activated titanium halide salicylaldiminato complexes functionalized with ω-vinylalkoxy
groups and containing tert-butyl substituents in the phenoxide moiety were studied. The catalytic activity of the
new group of activated complexes is strongly affected by the position of the ω-vinylalkoxy functional group and
by the number and position of substituents in the phenoxide moiety. These factors determine the ratio of the ho-
mogeneous and heterogeneous steps of the polymerization as a result of the catalyst self-immobilization onto the
polymer formed, and also the molecular characteristics of the polymer obtained at 20, 40, and 60°С and ethylene
pressure of 0.4 MPa. The possibility and conditions of preparing ultra-high-molecular-weight polyethylene with
improved morphology were revealed.
DOI: 10.1134/S1070427212090170
This study continues our research into specific
features of ethylene polymerization [1–4]. As self-
immobilizing catalytic systems we used titanium halide
salicylaldiminato complexes of various structures,
functionalized with ω-vinylalkoxy groups and activated
with methylalumoxane (MAO).
complexes [3-t-Bu-2-O-C6H3СH=N(C6F5)]TiCl2/МАО
for the same purposes was examined in the Netherlands
[7–9].
In this study we prepared new functionalized
bis(salicylaldiminato)complexesdifferingintheposition
(o- or p-) and length of ω-vinylalkoxy substituent and
examined how the ligand surrounding of the complex
and hence of the catalytic system affects its capability
for self-immobilization and, correspondingly, for
preservation of the “living” polymerization mechanism
and of the properties of the polyethylene formed.
Theinterestincatalystsofthistypeisduetothefactthat
catalysts based on functionalized bis(salicylaldiminato)
complexes can be efficiently used for preparing ultra-
high-molecular-weight polyethylene (UHMWPE) with
improved morphology, which facilitates its processing
into high-strength high-modulus tapes and fibers [5,
6]. It should be noted that, practically simultaneously
with our study and independently of it, the possibility
of using catalysts based on bis(salicylaldiminato)
EXPERIMENTAL
Ethylene was additionally purified by passing
1404

MULTICENTERED SELF-IMMOBILIZED ETHYLENE POLYMERIZATION
1405
through columns packed with calcined alumina. The
ethylene content was no less than 99.9%, and the dew
point was from –45 to –60°С. Argon of premium grade
was additionally dried by passing through columns
packed with calcined alumina. After drying, the dew
point did not exceed –60°С. Polymethylalumoxane
(Aldrich) was used as 10% solution in toluene. Toluene
of analytically pure grade was dried twice with freshly
calcined alumina and distilled from sodium metal under
argon just before use. Ultrapure grade isopropyl alcohol
was used without additional treatment. The viscosity
of polymer solutions was measured in an Ubbelohde
capillary viscometer in decalin at 135°С. The viscosity-
average molecular weight (Mη) of the polymers was
calculated from the intrinsic viscosity using the equation
[η] = 6.2 × 10–4М0.7 [10]. The molecular-weight
characteristics of the polymers (Mw and Mw/Mn) were
determined by gel permeation chromatography with an
Alliance GPCV2000 chromatograph (Waters, USA),
equipped with НТ3 and НТ5 Styragel columns (Waters),
at 150°С in 1,2,4-trichlorobenzene. The thermal
properties (melting point, enthalpy of phase transitions)
of the polymers were studied by differential scanning
calorimetry with a DSC-60 device (Shimadzu). The
structures of the polymers were determined from the IR
spectra, recorded with a Shimadzu FTIR-8300 Fourier
spectrometer in the absorption range 500–2500 cm–1.
Ethylene polymerization in the presence of homoge-
neous catalysts [titanium chloride bis(salicylaldiminato)
complexes] was performed in a 200 cm3. The reactor
was charged with the calculated amounts of toluene
and catalytic system components (catalyst and MAO)
through a nipple under argon countercurrent using med-
ical syringes. The mixture was saturated with ethylene
at the automatically maintained pressure of 0.4 MPa
with stirring at 1300 rpm. Simultaneously, the mixture
was heated to the working temperature of 20–60°С. Af-
ter a definite time, the reaction was stopped by adding
a deactivating mixture (50 ml of isopropyl alcohol and
2–3 ml of hydrochloric acid). The polymeric product
was filtered off, washed with alcohol and water, and
dried at 60°С in a vacuum to constant weight.
We examined the catalytic activity in ethylene
polymerization of MAO-activated titanium chloride
bis(salicylaldiminato)
complexes
1–10
with
ω-vinylalkoxy groups in the p- (1–6) and m-positions
(7–10) of the phenyl ring at the imine nitrogen atom.
1–6, where
7–10, where
R1
R2
n
R1
R2
n
R1
R2
n
R1
t-Bu t-Bu
10 t-Bu t-Bu
R2
n
1
2
3
t-Bu
t-Bu
t-Bu
H
H
H
1
2
3
4
5
6
t-Bu t-Bu
t-Bu t-Bu
t-Bu t-Bu
1
2
3
7
8
t-Bu
t-Bu
H
H
1
2
9
1
2
Thesalidylaldimineligandswerepreparedbyreactions
of 3-tert-butyl- and 3,5-di-tert-butylsalicyladlehydes
with hydrochlorides of p-allyloxyaniline (n = 1), p-[(but-
3-enyl)oxy]aniline (n = 2), and p-[(pent-4-enyl)oxy]
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 85 No. 9 2012

1406
IVANCHEVA et al.
Scheme 1.
=
=
aniline (n = 3) or with the corresponding m-substituted
anilines (n = 1, 2) in the presence of triethylamine in
refluxing methanol. The yields of the imines were
almost quantitative (92–99%) (Scheme 1).
IR spectra were recorded with a Vector 22 spectrometer
from samples pelletized with KBr. Elemental analysis
was performed with a Euro EA 3000 CHNS analyzer.
The IR spectra of the complexes contain absorption
bands at 437–478, (Ti–N vibrations), 524–566 (Ti–O
vibrations), and 1596–1610 cm–1 (N=CH vibrations).
The complexes were prepared in one step by the
reactions of the ligands with TiCl2(OPri)2 [11, 12] in
toluene at room temperature. Complexes of titanium(IV)
dichloride were obtained in high yields (85–93%)
(Scheme 2).
The 1Н NMR spectra of the complexes were recorded
onaBrukerАV-400deviceoperatingat400.13MHz.The
1
In the H NMR spectra of the complexes, there
are closely located signals of HC=N protons at
7.67–8.22 ppm, suggesting the presence of several
stereoisomeric forms. Despite the fact that these signals
are singlets, they were described in [11] as multiplets,
and this description became commonly accepted. The
other protons are manifested as multiplets because of
mutual overlap of the corresponding signals of specific
stereoisomers. The OH signals observed in the spectra
of the imines are absent in the spectra of the complexes.
Scheme 2.
Synthesis of 1–10 (general procedure). A mixture
of 2.3 mmol of aryl-substituted salicylaldimine, 10 ml
of absolute methylene chloride, and 4.25 g of a toluene
solution containing 0.273 g (1.15 mmol) of TiCl2(OPri)2
was stirred at room temperature under argon for 24 h.
The solvent from the resulting dark red solution was
distilled off in a water-jet-pump vacuum, and the residue
was washed on the filter with hexane (2 × 2 ml) and kept
for 1 h in an oil-pump vacuum at 100°С. The complexes
were obtained as red-brown powders.
Bis{2-[(4-allyloxyphenylimino)methyl]-6-tert-
butylphenoxy}titanium(IV) dichloride 1. Yield
94%. IR spectrum, ν, cm–1: 1606 (C=N), 554 (Ti–O),
1
455 (Ti–N). Н NMR spectrum, δ, ppm: 1.22–1.61 m
(18Н, С(СН3)3), 4.36–4.54 m (4H, ОСН2–СН=СН2),
5.23–5.46 m (4H, ОСН2–СН=СН2), 5.86–6.08 m (2H,
ОСН2–СН=СН2), 6.52–7.44 m (14Нar), 7.92–8.01 m
(2H, СH=N). Found, %: С 65.08, H 6.00, N 3.77,
Cl 9.70. C40H44Cl2N2O4Ti. Calculated, %: С 65.31,
H 6.03, N 3.81, Cl 9.64.
=
=
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MULTICENTERED SELF-IMMOBILIZED ETHYLENE POLYMERIZATION
1407
Yield 96%. IR spectrum (KBr), ν, cm–1: 1609 (C=N),
573 (Ti–O), 471 (Ti–N). Н NMR spectrum (CDCl3),
Bis{2-{[4-(but-3-enyloxy)phenylimino]methyl}-6-
tert-butylphenoxy}titanium(IV) dichloride 2. Yield
90%. IR spectrum (KBr), ν, cm–1): 1608 (C=N), 560
1
δ, ppm: 1.25–1.64 m [36Н, С(СН3)3], 1.64–1.94 m
(4Н, ОСН2–СН2–СН2–СН=СН2), 2.15–2.27 m (4Н,
ОСН2–СН2–СН2–СН=СН2), 3.75–4.02 m (4Н, ОСН2–
СН2–СН2–СН=СН2), 4.98–5.11 m (4Н, ОСН2–СН2–
СН2–СН=СН2), 5.76–5.93 m (2Н, ОСН2–СН2–СН2–
СН=СН2), 6.51–7.55 m (12Har), 7.93–8.04 m (2Н,
СH=N). Found, %: С 69.04, H 7.64, N 3.15, Cl 7.70.
C52H68Cl2N2O4Ti. Calculated, %: С 69.10, H 7.58,
N 3.10, Cl 7.84.
1
(Ti–O), 450 (Ti–N). Н NMR spectrum (CDCl3), δ,
ppm: 1.40–1.61 m (18Н, С(СН3)3), 2.41–2.60 m (4H,
ОСН2–CН2–СН=СН2), 3.84–4.07 m (4H, ОСН2–CH2–
СН=СН2), 5.01–5.22 m (4H, ОСН2–CH2–СН=СН2),
5.79–5.98 m (2H, ОСН2–CH2–СН=СН2), 6.54–7.45 m
(14Har), 7.94–8.18 m (2H, СH=N). Found, %: С 66.37,
H 6.48, N 3.77, Cl 9.34. C42H48Cl2N2O4Ti. Calculated,
%: С 66.06, H 6.34, N 3.67, Cl 9.29.
Bis{2-{[4-(pent-4-enyloxy)phenylimino]methyl}-
6-tert-butylphenoxy}titanium(IV) dichloride 3.
Yield 95%. IR spectrum (KBr), ν, cm–1: 1607 (C=N),
Bis{2-[(3-allyloxyphenylimino)methyl]-6-tert-
butylphenoxy}titanium(IV) dichloride 7. Yield
93%. IR spectrum, ν, cm–1: 1597 (C=N), 574 (Ti–O),
1
1
563 (Ti–O), 449 (Ti–N). Н NMR spectrum (CDCl3),
458 (Ti–N). Н NMR spectrum, δ, ppm: 1.29–1.52 m
δ, ppm: 1.31–1.61 m (18H, С(СН3)3), 1.73–1.93 m
(4H, ОСН2–СН2–СН2–СН=СН2), 2.13–2.27 m (4Н,
ОСН2–СН2–СН2–СН=СН2), 3.76–3.98 m (4H, ОСН2–
СН2–СН2–СН=СН2), 4.99–5.06 m (4H, ОСН2–СН2–
СН2–СН=СН2), 5.75–5.86 m (2H, ОСН2–СН2–СН2–
СН=СН2), 6.51–7.42 m (14Har), 7.91–8.01 m (2H,
СH=N). Found, %: С 66.39, H 6.61, N 3.48, Cl 9.00.
C44H52Cl2N2O4Ti. Calculated, %: С 66.75, H 6.62, N
3.54, Cl 8.96.
[18Н, С(СН3)3], 4.30–4.60 m (4H, ОСН2–СН=СН2),
5.22–5.47 m (4H, ОСН2–СН=СН2), 5.85–6.13 m (2H,
ОСН2–СН=СН2), 6.85–7.52 m (14Нar), 8.12–8.22 m
(2H, СH=N). Found, %: С 65.21, H 6.19, Cl 9.52,
N 3.65. C40H44Cl2N2O4Ti. Calculated, %: С 65.31,
H 6.03, Cl 9.64, N 3.81.
Bis{2-{[3-(but-3-enyloxy)phenylimino]methyl}-6-
tert-butylphenoxy}titanium(IV) dichloride 8. Yield
93%. IR spectrum (KBr), ν, cm–1: 1599 (C=N), 573
1
Bis{2-[(4-allyloxyphenylimino)methyl]-4,6-di-
tert-butylphenoxy}titanium(IV) dichloride 4. Yield
97%. IR spectrum, ν, cm–1): 1608 (C=N), 569 (Ti–O),
(Ti–O), 459 (Ti–N). Н NMR spectrum (CDCl3), δ,
ppm: 1.33–1.62 m [18Н, С(СН3)3], 2.42–2.54 m (4H,
ОСН2–CН2–СН=СН2), 3.62–4.00 m (4H, ОСН2–CH2–
СН=СН2), 5.08–5.21 m (4H, ОСН2–CH2–СН=СН2),
5.76–5.97 m (2H, ОСН2–CH2–СН=СН2), 6.57–7.64 m
(14Har), 7.97–8.12 m (2H, СH=N). Found, %: С 65.81,
H 6.38, N 3.49, Cl 9.36. C42H48Cl2N2O4Ti. Calculated,
%: С 66.06, H 6.34, N 3.67, Cl 9.29.
1
471 (Ti–N). Н NMR spectrum, δ, ppm: 1.26–1.38 m
(36Н, С(СН3)3), 4.34–4.57 m (4H, ОСН2–СН=СН2),
5.23–5.47 m (4H, ОСН2–СН=СН2), 5.92–6.05 m (2H,
ОСН2–СН=СН2), 6.51–7.46 m (12Har), 7.99–8.03 m
(2H, СH=N). Found, %: С 67.87, H 7.07, Cl 8.40, N
3.38. C48H60Cl2N2O4Ti. Calculated, %: С 68.00, H 7.13,
Cl 8.36, N 3.30.
Bis{2-[(3-allyloxyphenylimino)methyl]-4,6-di-
tert-butylphenoxy}titanium(IV) dichloride 9. Yield
93%. IR spectrum, ν, cm–1: 1599 (C=N), 567 (Ti–O),
Bis{2-{[4-(but-3-enyloxy)phenylimino]methyl}-
4,6-di-tert-butylphenoxy}titanium(IV) dichloride 5.
Yield 95%. IR spectrum (KBr), ν, cm–1: 1609 (C=N),
572 (Ti–O), 473 (Ti–N). 1Н NMR spectrum (CDCl3), δ,
ppm: 1.27–1.63 m [36Н, С(СН3)3], 2.41–2.60 m (4H,
ОСН2–CН2–СН=СН2), 3.81–4.07 m (4H, ОСН2–CH2–
СН=СН2), 5.09–5.23 m (4H, ОСН2–CH2–СН=СН2),
5.78–5.98 m (2H, ОСН2–CH2–СН=СН2), 6.52–7.80 m
(12Har), 7.94–8.19 m (2H, СH=N). Found, %: С 68.45,
H 7.54, N 3.11, Cl 7.91. C50H64Cl2N2O4Ti. Calculated,
%: С 68.57, H 7.37, N 3.20, Cl 8.10.
1
469 (Ti–N). Н NMR spectrum, δ, ppm: 1.22–1.64 m
[36Н, С(СН3)3], 4.12–4.25 m (4H, ОСН2–СН=СН2),
5.21–5.47 m (4H, ОСН2–СН=СН2), 5.83–6.11 m (2H,
ОСН2–СН=СН2), 6.54–7.49 m (12Har), 8.08–8.12
m (2H, СH=N). Found, %: С 67.52, H 7.15, N 3.14,
Cl 8.50. C48H60Cl2N2O4Ti. Calculated, %: С 68.00,
H 7.13, N 3.30, Cl 8.36.
Bis{2-{[3-(but-3-enyloxy)phenylimino]methyl}-
4,6-di-tert-butylphenoxy}titanium(IV) dichloride 10.
Yield 88%. IR spectrum (KBr), ν, cm–1: 1599 (C=N),
573 (Ti–O), 476 (Ti–N). 1Н NMR spectrum (CDCl3), δ,
ppm: 1.33–1.48 m [36Н, С(СН3)3], 2.47–2.60 m (4H,
Bis{2-{[4-(pent-4-enyloxy)phenylimino]methyl}-
4,6-di-tert-butylphenoxy}titanium(IV) dichloride 6.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 85 No. 9 2012

1408
IVANCHEVA et al.
ОСН2–CН2–СН=СН2), 3.96–4.09 m (4H, ОСН2–CH2–
СН=СН2), 5.07–5.22 m (4H, ОСН2–CH2–СН=СН2),
5.81–5.98 m (2H, ОСН2–CH2–СН=СН2), 6.83–7.46 m
(12Har), 7.60–7.71 m (2H, СH=N). Found, %: С 68.76,
H 7.47, N 3.08, Cl 7.96. C50H64Cl2N2O4Ti. Calculated,
%: С 68.57, H 7.37, N 3.20, Cl 8.10.
linker, at all the examined temperatures, we obtained
UHMWPE.
The results we obtained show that, in the series
of the examined catalysts, depending on the ligand
surrounding (substituents in phenoxy groups, position
of the functional ω-vinylalkoxy group in the aniline
moiety), the “living” polymerization mechanism can
change, leading to a decrease in the molecular weight
of the PE formed.
The results of studying the kinetic features of ethylene
polymerization at 20, 40, and 60°С on complexes 1–10
are given in Table 1. This temperature interval was
chosen so as to improve the ordering of the structure of
the UHMWPE obtained [13, 14].
When analyzing the results (catalytic activity of the
systems and M of PE), we should take into account
that, with an increase in temperature, the ethylene
concentration in the solution decreases, which leads
to a decrease in the polymerization rate and M of the
polymer. Furthermore, with an increase in temperature,
the catalytic system may become unstable [15], which
will also affect the polymerization rate and М of the
polymer.
Table 1 shows that the catalytic activity and the
molecular weights (М) of the PE samples obtained
depend on the structural features of the complexes
used: nature and position of substituents in the phenoxy
group, number of CH2 groups in the ω-vinylalkoxy
functional group, and position of this group, as it was
noted previously in studying related functionalized
salicylaldiminato complexes with cumyl substituents
in the phenoxy group [4]. Attentive analysis of
Table 1 of this study and of Table 1 of [4] shows
that, whereas with the cumyl-substituted analogs
UHMWPE was obtained practically always, with
the tert-butyl-substituted analogs in many cases the
“living” polymerization mechanism was disturbed.
Most frequently this is observed with an increase in
the length of the ω-vinylalkyl chain in the p-position of
the aniline moiety (complexes 2, 3, 5, and 6).
Completing the discussion of Table 1, we can note
that the catalysts based on functionalized tert-butyl-
substituted systems allow preparation of UHMWPE
with М several times lower [(1000–3000) × 103
g mol–1]
compared to the systems based on the cumyl-substituted
complexes. Nevertheless, the PE samples obtained have
high crystallinity (75–85%), high melting point, and
low content of methyl and vinyl groups, suggesting
insignificant role of chain-transfer reactions in the
polymerization.
In contrast to homogeneous catalysts based on
The group of tert-butyl-substituted functionalized
salicylaldiminato complexes only slightly differs in the
catalytic activity from the complexes considered in [4].
As for the molecular weight of the polymers formed
in the presence of complexes 1–10, the dependence
of М on the structure of the complexes and on the
polymerization temperature is considerably more
complex than we expected. Whereas with the cumyl-
substituted complexes we always obtained UHMWPE,
irrespective of the structure of the complex and
polymerization temperature [4], with the systems based
on the tert-butyl-substituted complexes UHMWPE
was obtained only in the case of complexes 1, 4, and
7–10. It should be noted that, in the systems with the
ω-vinylalkoxy group in the p-position, the polyethylene
formed in the presence of the complexes with n = 2 and
3 (2, 3, and 5) at 40 and 60°С is not UHMWPE. When
using the systems with the ω-vinylalkoxy group in the
m-position, irrespective of the length of the alkylene
MAO-activated
bis(salicylaldiminato)
complexes
[3-t-Bu-2-O-C6H3СH=N(C6F5)]TiCl2, used in [7–9,
13, 14], the catalytic systems we used, based on MAO-
activated substituted salicylaldiminato complexes of
various structures, undergo self-immobilization in the
course of polymerization. Therefore, we examined
how the self-immobilization and its features affect the
polymerization rate and the properties of the UHMWPE
obtained. Figures 1 and 2 show the kinetic curves of
polymerization (curves of ethylene uptake in time)
in relation to the structure of the complexes and the
polymerization temperature.
The shape of the uptake curves (Fig. 1) shows that
the initial higher rate of ethylene uptake corresponds to
the homogeneous polymerization. The polymerization
rate gradually decreases with time, and the process be-
comes heterogeneous. In this step of the polymerization,
the catalytic system is self-immobilized on the poly-
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MULTICENTERED SELF-IMMOBILIZED ETHYLENE POLYMERIZATION
1409
Table 1. Characteristics of products of ethylene polymerization on functionalized bis(salicylaldiminato) complexes 1–10 of
Ti(IV) dichloride, activated with methylalumoxane. Polymerization conditions: toluene volume 50 ml, pressure 0.4 MPa,
МАО/Ti = 500/1 (mol/mol), τ = 1 h
Content of groups b
Catalytic
activity A,
Polymeriz-
ation tempera-
ture, °C
Tm, a
Degree of
crystallinity,a
%
Ti,
Mη × 10–3,
g mol–1
ΔH,a
J g–1
Catalytic
complex
Polymer
yield, g
kgPE
°C
μmol
–СН3 –СН=СН2
(molcat
MPa h)–1
1
2
3
4
20
0.516
4.940
22930
2060
140.6 246
83
0
0.04
40
60
20
40
60
20
40
60
20
40
0.500
0.500
1.24
8.127
6.511
7.567
6.886
5.951
6.984
9.134
6.347
7.09
40630
32550
15260
17530
15150
16260
21340
15695
17730
20280
2470
2800
1040
760
141.9 250
142.8 236
140.3 242
139.6 249
140.8 245
141.1 228
141.5 218
140.7 225
141.6 236
142.7 237
85
80
82
85
84
78
74
77
81
81
0.74
0.41
0.05
0.05
0.10
0
0.036
0.035
0.06
0.06
0.06
0.04
0.05
0.05
0.03
0.02
0.982
0.992
1.074
1.070
1.011
1.00
760
1070
940
0
850
0
2400
3200
0
1.00
8.11
0
60
20
1.00
0.57
6.14
3.96
15350
17370
3260
1100
143.5 240
141.3 218
82
74
0
0
0.03
0.04
5
6
40
0.63
7.63
30230
750
140.6 228
78
0
0.045
60
20
0.68
0.66
5.34
5.15
19500
21460
710
141.0 224
141.75 225
76
76
0.1
0
0.05
1300
0.035
40
0.55
3.44
15640
1080
141.2 211
72
0
0.04
60
20
40
60
20
40
60
20
40
60
20
40
60
0.55
1.02
3.00
7.715
8.242
7.727
14.06
12.05
5.987
2.40
13630
18910
17760
15830
35790
28690
14260
9260
760
141.3 211
141.9 236
141.4 236
141.0 246
141.8 246
141.3 253
140.9 255
142.3 225
142.1 218
141.1 227
140.3 228
141.8 220
141.6 224
72
81
81
84
84
86
87
77
74
77
78
75
76
0
0
0.04
0.02
0.04
0.04
0.03
0.03
0.04
0.03
0.035
0.03
0.03
0.04
0.04
7
8
1800
1800
1150
1500
1300
1700
1900
1500
1000
1680
1460
1200
1.16
0
1.22
0.15
~0
~0
0.05
0
0.982
1.050
1.050
0.648
0.700
0.580
0.628
0.628
0.685
9
3.48
12430
14440
18470
21100
9350
0
3.35
0
10
4.625
5.30
0
0
2.65
0
a DSC data. b IR data.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 85 No. 9 2012

1410
IVANCHEVA et al.
mer formed. The self-immobilization rate depends on
the length of the ω-vinylalkoxy group (number of СН2
groups). This follows both from the amount the complex
grafted to the polymer in the first minutes of the polym-
erization and from М of the PE obtained. The amount
of the catalyst that was not incorporated in the polymer
chain was determined with an SF-2000 spectrophotom-
eter from the solution absorption intensity in the range
400–500 nm [2]. As shown in Fig. 1 for catalytic sys-
tem 1 (n = 1), the immobilization starts from the first
minutes and is practically complete by the 20th minute.
The amount of the catalyst immobilized on the polymer
chains reaches 65–70%. After that, the polymerization
rate remains practically constant and fairly high. With
system 2 (n = 2), the reaction rate is the lowest, the im-
mobilization is complete by the 30th–40th minute, and,
correspondingly, М of the polymer drastically decreases
(760 × 103). With system 3 (n = 3), the immobilization
is weak.
τ, min
Fig. 1. Kinetic curves of ethylene polymerization at 40°С.
Catalytic complex: (1) 1, (2) 2, and (3) 3. (W) Polymerization
rate and (τ) time.
The kinetic curves shown in Figs. 1 and 2 confirm
that, with complex 1, the process initially occurs in the
homogeneous system, with gradual immobilization
of the catalyst on the polymer formed, which leads
to a decrease in the polymerization rate to the level
characteristic of the supported catalyst. As seen
from Fig. 2, the reaction temperature affects the self-
immobilization rate and, as a consequence, the rate at
which the catalyst passes into the immobilized state.
With complex 1 at 40°С, the polymerization rate is the
highest. At higher temperature (60°С), the rate of the
heterogeneous polymerization decreases.
τ, min
Fig. 2. Kinetic curves of ethylene polymerization in the presence
of complex 1. Temperature, °C: (1) 20, (2) 40, and (3) 60. (W)
Polymerization rate and (τ) time.
In Fig. 3, the kinetic curves of complex 3 at 20 and
60°С differ throughout the process only slightly, and
at 40°С higher rate is observed in the period when the
Table 2. Variation of the polydispersity of PE samples in
the course of polymerization in the presence of complex 3.
Polymerization conditions: toluene volume 50 ml, pressure
0.4 MPa, T = 40°C, 1.0 μmol Ti, MAO/Ti = 500/1 (mol/mol)
Мn × 10–3
Mw × 10–3
g mol–1
τ, min
Mw/Mn
2
299
622
2.08
10
20
60
335
339
373
741
766
943
2.21
2.26
2.53
τ, min
Fig. 3. Kinetic curves of ethylene polymerization in the presence
of complex 3. Temperature, °C: (1) 20, (2) 40, and (3) 60. (W)
Polymerization rate and (τ) time.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 85 No. 9 2012

MULTICENTERED SELF-IMMOBILIZED ETHYLENE POLYMERIZATION
1411
log M
log M
Fig. 4. Differential MWD curves of PE. Polymerization
temperature 40°С, ethylene pressure 0.4 MPa, catalyst 3. Time,
min: (1) 2, (2) 20, and (3) 60. (Mw, Mn, Mp) Weight-average,
number-average, and peak molecular weights, respectively; the
same for Fig. 5.
Fig. 5. Differential MWD curves of PE. Polymerization
temperature 40°С, ethylene pressure 0.4 MPa, catalyst 10. Time,
min: (1) 2, (2) 5, and (3) 60.
ω-vinylalkoxy functional group and by the number
and position of substituents in the phenoxy group
of the complex. These factors determine the ratio
of the homogeneous and heterogeneous steps of
the polymerization as a result of the catalyst self-
immobilization onto the forming polymer, and also the
molecular characteristics of the polymer obtained. Our
data allow the choice of the best catalytic system and
best polymerization conditions for preparing UHMWPE
with the optimal molecular weight and improved
morphology.
process is homogeneous, and after 20 min the curves
also differ insignificantly.
Transition from the homogeneous polymerization
to the heterogeneous mechanism in the systems under
consideration can seemingly lead to broadening of the
molecular-weight distribution (MWD) of the polymers
and to deterioration of the macromolecular ordering,
which may affect the extent of interweaving of the
macromolecules [7, 13]. To check this experimentally,
we recorded the differential MWD curves of PE (Fig. 4)
obtained on catalyst 3 at different polymerization times.
The choice of the polymer sample was governed by the
M values suitable for measurements.
ACKNOWLEDGMENTS
The authors are grateful to M.G. Eremeeva for
performing experiments on ethylene polymerization.
The curve symmetry is not appreciably distorted,
which confirms smooth course of polymerization,
irrespective of the degree of immobilization. Data on the
polydispersity of the polymer samples obtained on the
same catalyst 3 in relation to the polymerization time
are given in Table 2.
The study was supported by the Russian Foun-
dation for Basic Research, project no. 11-03-12016
ofi-m-2011.
REFERENCES
The “living” polymerization mechanism is confirmed
by the differential MWD curves of PE formed with
complex 10 containing the ω-vinylalkoxy group (n = 2)
in the m-position (Fig. 5).
1. Ivancheva, N.I., Malinskaya, M.Yu., Oleinik, I.I., et al.,
Dokl. Ross. Akad. Nauk, 2007, vol. 417, no. 2, pp. 213–
216.
2. Ivanchev, S.S., Vasileva, M.Yu., Ivancheva, N.I., et
al., Vysokomol. Soedin., 2009, Ser. B, vol. 51, no. 8,
pp. 1538–1545.
CONCLUSION
The catalytic activity of the new group of activated
complexes is strongly affected by the position of the
3. Ivancheva, N.I., Badaev, V.K., Sviridova, E.V., et al., Zh.
Prikl. Khim., 2011, vol. 84, no. 1, pp. 118–123.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 85 No. 9 2012

1412
IVANCHEVA et al.
4. Ivancheva, N.I., Sanieva, D.V., Fedorov, S.P., et al., Izv.
10. Chiang, R., J. Polym. Sci., 1959, vol. 36, pp. 91–102.
Ross. Akad. Nauk, Ser. Khim., 2012, no. 4, pp. 833–839.
11. Matsui, S., Mitani, M., Saito, J., et al., J. Am. Chem. Soc.,
2001, vol. 123, no. 28, pp. 6847–6855.
5. RF Patent Appl. 2010147266 А, positive decision of
March 16, 2012.
12. Gagieva, S.Ch., Sukhova, T.A., Savinov, D.V., et al., Izv.
Ross. Akad. Nauk, Ser. Khim., 2003, no. 8, pp. 1605–
1609.
6. Ozerin, A.N., Ivanchev, S.S., Chvalun, S.N., et al., Vyso-
komol. Soedin. (in press).
7. Rastogi, S., Yao, Y., Ronca, S., et al., Macromolecules,
13. Pandey, A., Champouret, Y., and Rastogi, S., Macromol-
ecules, 2011, vol. 44, pp. 4952–4960.
2011, vol. 44, pp. 5558–5568.
8. WO Patent 2010/079173 A1, 2010.
9. WO Patent 2010/079174 A2, 2010.
14. Talebi, S., Duchateau, R., Rastogi, S., et al., Macromol-
ecules, 2010, vol. 43, pp. 2780–2788.
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