Chemistry Reference
In-Depth Information
nBuLi
THF
Br
P
Br
P
n+2
3
3
P
P
n
3
3
polymer 1
O
O
polymer 1
H
+
H
n
n
n
x
H
A preparation of block copolymers by “living” ring-opening olefin metathesis polymerization was
reported [
417
]. Initially, norbornene or
5
-cyclopen-
tadienyl)titanacyl butane. The resulting living polymers are then reacted with terephthaldehyde to
form polymers with terminal aldehyde groups. The aldehyde groups in turn initiate polymerizations
of
exo
-dicyclopentadiene are polymerized by bis(
Z
-butyldimethylsilyl vinyl ether by aldol-group transfer polymerizations [
418
]. Following is an
illustration of the process:
t
O
H
n}1
O
+
Si
Si
O
H
O
n-1
n}1
O
Si
Subsequently, the terminal aldehyde group is reduced with NaBH
4
and the silyl groups cleaved off
by treatment with tetrabutylammonium fluoride to produce a hydrophobic-hydrophilic A—B diblock
copolymers.
