Chemistry Reference
In-Depth Information
PMAEDA
PAEDA
PABDA
100
PMAEDA
PABDA
PAEDA
80
60
40
20
0
0
100
200
300
400
500
600
30
60
90
120
150
Temperature (ºC)
Temperature (ºC)
Figure 4.13
DSC and TGA traces of PAEDA, PABDA and PMAEDA polymers
prepared by ATRP. Reproduced with permission from Y. Zheng, K. Yao, J.S. Lee,
D. Chandler, J. Wang, C. Wang; F. Chu and C. Tang,
Macromolecules
, 2010,
43
,
14, 5922. ©2010 American Chemical Society [5]
4.5 Reversible Addition Fragmentation Chain Transfer of Acrylic
Monomers
RAFT polymerisation was carried out using two monomers, a methacrylate (MAEDA)
and an acrylate (AEDA). The process of RAFT polymerisation is very similar to free
radical polymerisation; however the final molecular weight of polymers, as well as
the molecular weight distribution, for these two radical polymerisation techniques
should differ. As previously mentioned, RAFT is a controlled radical polymerisation
technique. A desired molecular weight can be obtained by adjusting the molar ratio
of monomer to RAFT agent. The first polymerisation system consisted of monomer
(MAEDA), initiator (
azobisisobutyronitrile
(AIBN)) and RAFT transfer agent (cumyl
dithiobenzoate, CDB). The solvent was toluene. The molar ratio used for these
materials was: [MAEDA]:[CDB]:[AIBN] = [100]:[1]:[0.1]. The mixture was employed
for three cycles of freeze-pump-thaw. The experiment was carried out at 100 °C in
a Schlenk flask. The reaction mechanism is shown in
Figure 4.14
.
