Chemistry Reference
In-Depth Information
-caprolactone) with 2,2,6,6-
tetramethylpiperdine-1-oxyl (TEMPO) at one end by anionic polymerization of caprolactone using an
aluminum tri(4-oxy-TEMPO) initiator. The TEMPO-supported polycaprolactone behaved as a poly-
meric counter radical for a controlled/“living” radical polymerization of styrene to form block
copolymers [
436
].
Also, Kotani et al. [
437
] reported using controlled/“living” atom transfer radical polymerization
(ATRP) to form block copolymers of ethyl and
In a similar manner, Yoshida and Osagawa [
436
] synthesized poly(
e
-butyl methacrylates. A ternary initiating system that
consists of carbon tetrachloride, tris(triphenyl-phosphine)ruthenium dichloride [RuCl
2
(PPh
3
)
3
], and
aluminum compounds produced ABA triblock copolymers [
437
].
Huang and coworkers [
437
] reported preparation of a series of well-defined amphiphilic block
copolymers containing conjugated poly(fluorene) (PF) block and coil like poly(2-(dimethylamino)
ethyl methacrylate) (PDMAEMA). The block copolymers were synthesized through ATRP. The
reactions were initiated by a 2-bromoisobutyrate end-capped macroinitiator using CuCl/
1,1,4,7,10,10-hexamethyltriethylenetetramine as the catalyst.
Matron and Grubbs formed block copolymers by combining ring opening metathesis polymeriza-
tion with ATRP [
437
]. Use was made of fast initiating ruthenium metathesis catalyst to form three
different monotelechelic poly(oxa)norbornenes. The
n
ends were
functionized and ATRP
polymerizations of styrene and
-butyl acrylate followed.
Coca et al. [
438
] showed a general method of transforming living ring opening metathesis
polymerization into controlled/“living” atom transfer polymerizations to form block copolymers.
Ring opening polymerizations of norbornene or dicyclopentadiene were followed by Witting-like
reactions with
tert
-(bromomethyl)benzaldehyde to form efficient (ATP) macroninitiators for formation
of block copolymers with styrene [
478
]:
p
N
n
+
N
O
Mo
n
O
Mo
O
O
Other cationic ring opening polymerizations can also be transformed to ATRP to yield block
copolymers [
439
]. Thus, formation of block copolymers was initiated by poly(tetramethylene glycol)
containing one bromopropionyl end group. These were used to form block copolymers by ATP
polymerization of styrene, methyl methacrylate, and methyl acrylate.
Br
CuBr/Nbipy
HO
O
m
O
+
n
toluene/100°C
O
block copolymer
