Rosin-derived Polymers and their Progress in Controlled Polymerisation - Rosin-based Chemicals and Polymers - page 107

almost 2 days. The polymers obtained had a molecular weight of 11,400g/mol and
a PDI of approximately 2.0. Since the polymerisation was very slow in toluene, a
reaction was then performed using tetrahydrofuran (THF) as the solvent for 23 h at
80 °C. Although a low yield was obtained, a molecular weight of 29,100 g/mol and
a PDI of 1.3 showed that THF was a better solvent for the controlled polymerisation
( Figure 4.19 ). 1 H NMR spectrum of the obtained polymers had all the characteristic
proton peaks and these were clearly assigned ( Figure 4.18 ).
Figure 4.19 GPC traces of PAEDA prepared by RAFT in THF at 80 o C and by free
radical polymerisation in THF at 80 o C
To compare RAFT polymerisation with free radical polymerisation, a reaction was
conducted without the controlling agent (CDB) in THF at 80 °C for 21 h. The
molecular weight of the resulting polymer was 6,300 g/mol and the PDI was 1.97
( Figure 4.19 ). This demonstrated that RAFT resulted in not only a higher molecular
weight, but also a lower PDI.
In order to study the effects of the amount of CDB used, two reactions were run
simultaneously for 70 h at 80 °C in THF. According to the RAFT polymerisation
process described above, if the amount of RAFT agent is decreased the reaction rate