T. Higashihara1, R. Faust*2, K. Inoue1, and A. Hirao1, 1Tokyo Institute
of Technology, O-okayama 2-12-1, Meguro-ku, Tokyo 152-8552,
Japan, 2University of Massachusetts Lowell, 1 University Ave., Lowell,
MA 01854, USA
Email: thigashihara@polymer.titech.ac.jp
Tensile Stress (MPa)
Synthesis of Novel Multi-Functionalized Polyisobutylenes with
Benzyl Bromide Moieties and Their Application to AnB
Asymmetric Star and AnBAn Pompom Polymers
Introduction. There has been growing interest and research on
chain-end functionalized polymers with well-defined structures.
These functional groups in polymers make further construction and
modification possible…..
Experimental. Materials: All reagents were purchased from
Sigma-Aldrich Corp. (>99%) unless otherwise stated.
Synthesis of Chain-End(s) Functionalized PIBs with Benzyl
Bromide Moieties:
All reactions using the functionalized
1,1-diphenylalkyl anion obtained from 1:1 reaction of 1 and sBuLi
were carried out in sealed reactors equipped with break-seals under
high vacuum conditions (10-6 torr) …..
Results and Discussion.
Synthesis of Chain-End
Functionalized PIBs with Benzyl Bromide Moieties (Series 1 and 2):
A series of -chain-end functionalized PIBs with multiple benzyl
bromide moieties (PIB(BnBr)n; n = 2, 4, and 8, series 1) was first
synthesized by the iterative divergent methodology starting from
-chain-end functionalized PIB with one allyl chloride moiety
(PIB(AllylCl)1)…
CH3
CH3
CH2 C
H3C C
CH3
CH3
CH2 C
CH3
CH3
CH2 CH CH CH2
Ti2Cl9
CH3
CH3
CH2 C
H3C C
CH3
CH2 CH CH CH2 Cl
CH3
PIB(AllylCl)1
PIB
OSiMe2But
OSiMe2But
sBuLi
s
a
LiH
Bu
OSiMe2But
OSiMe2But
1
CH3
CH3
CH2 C
H3C C
PIB
PIB(SMP)2
CH3
TMS-Br
OSiMe2But
sBu
CH2 CH CH CH2
CH3
OSiMe2But
b
Br
PIB(BnBr)2
CH3
CH3
CH2 C
H3C C
PIB
CH3
sBu
CH2 CH CH CH2
CH3
Br
a
PIB
PIB(SMP)4
b
PIB
a
PIB
PIB(BnBr)4
b
PIB(SMP)8
PIB
PIB(BnBr)8
Scheme 1.
Table 1. Synthesis of Chain-End Functionalized PIBs with Benzyl
Bromide Moieties (Series 1 and 2)
type
Mn (kg/mol)
calcd
SEC
1
Mw/Mn
functionality
H NMR
SEC
calcd
1
H NMR
PIB(BnBr)2
6.14
5.70
6.38
1.06
2
2.00
PIB(BnBr)4
6.85
5.90
7.03
1.07
4
3.90
PIB(BnBr)8
8.26
7.97
8.01
1.06
8
7.93
3.99
(BnBr)2PIB(BnBr)2
35.9
31.5
35.3
1.04
4
(BnBr)4PIB(BnBr)4
37.3
38.1
36.8
1.05
8
(BnBr)8PIB(BnBr)8
40.1
40.6
39.8
1.04
16
7.90
16.0
22
20
18
16
14
12
10
8
6
4
2
0
A2BA2
20.7 MPa
444%
A4BA4
15.5 MPa
279%
A8BA8
12.6 MPa
338%
0
50
100
150
200
250
300
350
400
450
500
Tensile Strain (%)
Figure 1. Stress-strain plots for the films of AnBAn type pompom
polymers.
Conclusions. A novel series of multi-functionalized PIBs with
two, four, and eight benzyl bromide moieties at -chain-end or
,-chain-ends has been successfully synthesized by the iterative
divergent methodology…..
References.
(a) Hsieh, H. L.; Quirk, R. P. In Anionic Polymerization:
Principles and Practical Applications; Marcel Dekker: NY,
Basel, Switzerland, Hong Kong, 1996; Chapter 11. (b)
Hadjichristidis, N.; Pispas, S.; Pitsikalis, M. Prog. Polym. Sci.
1999, 24, 875–915.
[2] Hirao, A.; Hayashi, M. Macromolecules 1999, 32, 6450–60.
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