content from 1.3 to 0.1 mol%, keeping the Me 3 Al content at approximately
0.1 mol%.
Propene polymerization was conducted in heptane with 1 using dMAO and dMMAO
at 0
C under atmospheric pressure of propene. The results are shown in Table 1.
Both dMMAO and dMAO systems conducted polymerization, but the former
showed about 50 times higher activity than the latter. The polymers obtained with
dMMAO and dMAO had high M n values of 290,000 and 209,000, respectively, and
consequently the number of polymer chains (N) in the dMMAO system was 30 times
larger than in the dMAO system. The polydispersity (M w /M n ) of the polymer
obtained with the dMMAO system was narrow (M w /M n ¼ 1.16), whereas that with
the dMAO system was broad (M w /M n ¼ 3.52). The low N value and the broad M w /
M n in the dMAO system are mainly due to the poor solubility of dMAO in heptane.
MAO and MMAO did not show activity under the same conditions, probably due to
the formation of the heterodinuclear complex with the remaining R 3 Al.
The rate–time profile of propene polymerization with the dMMAO system is
illustrated in Fig. 2, indicating a steady rate after a certain induction period. The
Table 1 Effect of cocatalyst on propene polymerization with 1
a
Run Cocatalyst
Ti (μmol) Activity
b
M n
c (Â10
4
) M w /M n
c
N/Ti
d (mol/mol)
1
dMAO
20
7
20.9
3.52
0.02
2
dMMAO
20
321
29.2
1.16
0.46
3
dMMAO/SiO 2
20
235
66.1
1.34
0.15
4
dMMAO/SiO 2
10
89
124
1.43
0.03
5
dMMAO/Al 2 O 3 10
102
49.2
2.17
0.09
6
dMMAO/MgO
10
4
27.2
2.48
0.01
a
Polymerization conditions: heptane ¼ 30 mL, propene ¼ 1 atm, 0
C, polymerization time ¼
25 min, Al ¼ 8.0 mmol (Run 1–2), Al ¼ 4.0 mmol (Run 3–6)
b
kg-PP mol-Ti
À1 h
À1
c
Determined by GPC using universal calibration
d
Molar ratio of 1 and polymer chain calculated from yield and M n
Fig. 2 Rate–time profiles of
propene polymerization with
1 activated by dMMAO and
dMMAO/SiO 2 : squares,
dMMAO (Ti ¼ 20 μmol);
open circles, dMMAO/SiO 2
(Ti ¼ 20 μmol); filled circles,
dMMAO/SiO 2
(Ti ¼ 10 μmol); triangles,
MMAO (Ti ¼ 20 μmol) [12]
146
T. Shiono
0.1 mol%.
Propene polymerization was conducted in heptane with 1 using dMAO and dMMAO
at 0
C under atmospheric pressure of propene. The results are shown in Table 1.
Both dMMAO and dMAO systems conducted polymerization, but the former
showed about 50 times higher activity than the latter. The polymers obtained with
dMMAO and dMAO had high M n values of 290,000 and 209,000, respectively, and
consequently the number of polymer chains (N) in the dMMAO system was 30 times
larger than in the dMAO system. The polydispersity (M w /M n ) of the polymer
obtained with the dMMAO system was narrow (M w /M n ¼ 1.16), whereas that with
the dMAO system was broad (M w /M n ¼ 3.52). The low N value and the broad M w /
M n in the dMAO system are mainly due to the poor solubility of dMAO in heptane.
MAO and MMAO did not show activity under the same conditions, probably due to
the formation of the heterodinuclear complex with the remaining R 3 Al.
The rate–time profile of propene polymerization with the dMMAO system is
illustrated in Fig. 2, indicating a steady rate after a certain induction period. The
Table 1 Effect of cocatalyst on propene polymerization with 1
a
Run Cocatalyst
Ti (μmol) Activity
b
M n
c (Â10
4
) M w /M n
c
N/Ti
d (mol/mol)
1
dMAO
20
7
20.9
3.52
0.02
2
dMMAO
20
321
29.2
1.16
0.46
3
dMMAO/SiO 2
20
235
66.1
1.34
0.15
4
dMMAO/SiO 2
10
89
124
1.43
0.03
5
dMMAO/Al 2 O 3 10
102
49.2
2.17
0.09
6
dMMAO/MgO
10
4
27.2
2.48
0.01
a
Polymerization conditions: heptane ¼ 30 mL, propene ¼ 1 atm, 0
C, polymerization time ¼
25 min, Al ¼ 8.0 mmol (Run 1–2), Al ¼ 4.0 mmol (Run 3–6)
b
kg-PP mol-Ti
À1 h
À1
c
Determined by GPC using universal calibration
d
Molar ratio of 1 and polymer chain calculated from yield and M n
Fig. 2 Rate–time profiles of
propene polymerization with
1 activated by dMMAO and
dMMAO/SiO 2 : squares,
dMMAO (Ti ¼ 20 μmol);
open circles, dMMAO/SiO 2
(Ti ¼ 20 μmol); filled circles,
dMMAO/SiO 2
(Ti ¼ 10 μmol); triangles,
MMAO (Ti ¼ 20 μmol) [12]
146
T. Shiono