Living Radical Polymerizations read pg 313 Odian

1
Living Radical Polymerizations read pg 313 Odian
General points Conventional radicals have short
life times-usually lt 1s Living polymerization
seeks to lengthen these lifetimes
Keep R low so termination minimized
.
Typical R concs 10-7 10-8 M
R 10-1 - 10-3 M
2
Some new reactions
REDOX generation of radicals
Available for further reactions
dynamic equilibria
3
Radical addition to Dithionate esters
4
Nitroxides
A stable radical
TEMPO
DOES NOT INITIATE
5
Atom Transfer Radical Polymerization ATRP
R.
X-2 M2
R-X X- M
M
RM.
RMX M
XM2
Ligands are important as is the X group
e.g.
Typically X Br I and Ts are also known
6
So a good example of an initiator is
7
Some useful bits of the literature 1) Jin-Shan
Wang, Krzysztof Matyjaszewski J. Am. Chem. Soc.
1995,117, 5614
The first example
3
3
REDOX process
CuCl2
CuCl

8
(No Transcript)
9
Kato,Kamigaito, Sawamoto, Higashimura
Macromolecules 1996,28, 1721
Many other examples (477 papers since 1995)
10
Block copolymers by ATRP 100s of examples eg
Mao, Gan, Gan, Tam, Tan Polymer. 2005, 46,
10045
CuCl2
CuCl
11
Reversible Addition Fragmentation Termination
RAFT
12
(No Transcript)
13
The first example
Y. K. Chong, T.P. T. Le, G. Moad, E. Rizzardo, S.
H. Thang
Macromolecules (1999), 32, 2071
14
Using stable radicals
Veregin, Georges, Kazmaier Hamer Macromolecules
(1993), 26, 5316
.
.
X
X
M
.
MMMM
.
MMMMX
X
.
.
MMMM
X
M
MMMMMMMMMX
15
Nitroxides